Add the DragonFly cvs id and perform general cleanups on cvs/rcs/sccs ids. Most

[dragonfly.git] / contrib / gcc / final.c

/* Convert RTL to assembler code and output it, for GNU compiler.
   Copyright (C) 1987, 88, 89, 92-98, 1999 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

GNU CC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/* $FreeBSD: src/contrib/gcc/final.c,v 1.7.2.3 2002/06/20 23:12:26 obrien Exp $ */
/* $DragonFly: src/contrib/gcc/Attic/final.c,v 1.2 2003/06/17 04:23:59 dillon Exp $ */


/* This is the final pass of the compiler.
   It looks at the rtl code for a function and outputs assembler code.

   Call `final_start_function' to output the assembler code for function entry,
   `final' to output assembler code for some RTL code,
   `final_end_function' to output assembler code for function exit.
   If a function is compiled in several pieces, each piece is
   output separately with `final'.

   Some optimizations are also done at this level.
   Move instructions that were made unnecessary by good register allocation
   are detected and omitted from the output.  (Though most of these
   are removed by the last jump pass.)

   Instructions to set the condition codes are omitted when it can be
   seen that the condition codes already had the desired values.

   In some cases it is sufficient if the inherited condition codes
   have related values, but this may require the following insn
   (the one that tests the condition codes) to be modified.

   The code for the function prologue and epilogue are generated
   directly as assembler code by the macros FUNCTION_PROLOGUE and
   FUNCTION_EPILOGUE.  Those instructions never exist as rtl.  */

#include "config.h"
#include "system.h"

#include "tree.h"
#include "rtl.h"
#include "regs.h"
#include "insn-config.h"
#include "insn-flags.h"
#include "insn-attr.h"
#include "insn-codes.h"
#include "recog.h"
#include "conditions.h"
#include "flags.h"
#include "real.h"
#include "hard-reg-set.h"
#include "defaults.h"
#include "output.h"
#include "except.h"
#include "toplev.h"
#include "reload.h"
#include "intl.h"

/* Get N_SLINE and N_SOL from stab.h if we can expect the file to exist.  */
#if defined (DBX_DEBUGGING_INFO) || defined (XCOFF_DEBUGGING_INFO)
#include "dbxout.h"
#if defined (USG) || !defined (HAVE_STAB_H)
#include "gstab.h"  /* If doing DBX on sysV, use our own stab.h.  */
#else
#include <stab.h>
#endif

#endif /* DBX_DEBUGGING_INFO || XCOFF_DEBUGGING_INFO */

#ifdef XCOFF_DEBUGGING_INFO
#include "xcoffout.h"
#endif

#ifdef DWARF_DEBUGGING_INFO
#include "dwarfout.h"
#endif

#if defined (DWARF2_UNWIND_INFO) || defined (DWARF2_DEBUGGING_INFO)
#include "dwarf2out.h"
#endif

#ifdef SDB_DEBUGGING_INFO
#include "sdbout.h"
#endif

/* .stabd code for line number.  */
#ifndef N_SLINE
#define N_SLINE 0x44
#endif

/* .stabs code for included file name.  */
#ifndef N_SOL
#define N_SOL 0x84
#endif

#ifndef INT_TYPE_SIZE
#define INT_TYPE_SIZE BITS_PER_WORD
#endif

#ifndef LONG_TYPE_SIZE
#define LONG_TYPE_SIZE BITS_PER_WORD
#endif

/* If we aren't using cc0, CC_STATUS_INIT shouldn't exist.  So define a
   null default for it to save conditionalization later.  */
#ifndef CC_STATUS_INIT
#define CC_STATUS_INIT
#endif

/* How to start an assembler comment.  */
#ifndef ASM_COMMENT_START
#define ASM_COMMENT_START ";#"
#endif

/* Is the given character a logical line separator for the assembler?  */
#ifndef IS_ASM_LOGICAL_LINE_SEPARATOR
#define IS_ASM_LOGICAL_LINE_SEPARATOR(C) ((C) == ';')
#endif

#ifndef JUMP_TABLES_IN_TEXT_SECTION
#define JUMP_TABLES_IN_TEXT_SECTION 0
#endif

/* Last insn processed by final_scan_insn.  */
static rtx debug_insn = 0;

/* Line number of last NOTE.  */
static int last_linenum;

/* Highest line number in current block.  */
static int high_block_linenum;

/* Likewise for function.  */
static int high_function_linenum;

/* Filename of last NOTE.  */
static char *last_filename;

/* Number of basic blocks seen so far;
   used if profile_block_flag is set.  */
static int count_basic_blocks;

/* Number of instrumented arcs when profile_arc_flag is set.  */
extern int count_instrumented_arcs;

extern int length_unit_log; /* This is defined in insn-attrtab.c.  */

/* Nonzero while outputting an `asm' with operands.
   This means that inconsistencies are the user's fault, so don't abort.
   The precise value is the insn being output, to pass to error_for_asm.  */
static rtx this_is_asm_operands;

/* Number of operands of this insn, for an `asm' with operands.  */
static unsigned int insn_noperands;

/* Compare optimization flag.  */

static rtx last_ignored_compare = 0;

/* Flag indicating this insn is the start of a new basic block.  */

static int new_block = 1;

/* All the symbol-blocks (levels of scoping) in the compilation
   are assigned sequence numbers in order of appearance of the
   beginnings of the symbol-blocks.  Both final and dbxout do this,
   and assume that they will both give the same number to each block.
   Final uses these sequence numbers to generate assembler label names
   LBBnnn and LBEnnn for the beginning and end of the symbol-block.
   Dbxout uses the sequence numbers to generate references to the same labels
   from the dbx debugging information.

   Sdb records this level at the beginning of each function,
   in order to find the current level when recursing down declarations.
   It outputs the block beginning and endings
   at the point in the asm file where the blocks would begin and end.  */

int next_block_index;

/* Assign a unique number to each insn that is output.
   This can be used to generate unique local labels.  */

static int insn_counter = 0;

#ifdef HAVE_cc0
/* This variable contains machine-dependent flags (defined in tm.h)
   set and examined by output routines
   that describe how to interpret the condition codes properly.  */

CC_STATUS cc_status;

/* During output of an insn, this contains a copy of cc_status
   from before the insn.  */

CC_STATUS cc_prev_status;
#endif

/* Indexed by hardware reg number, is 1 if that register is ever
   used in the current function.

   In life_analysis, or in stupid_life_analysis, this is set
   up to record the hard regs used explicitly.  Reload adds
   in the hard regs used for holding pseudo regs.  Final uses
   it to generate the code in the function prologue and epilogue
   to save and restore registers as needed.  */

char regs_ever_live[FIRST_PSEUDO_REGISTER];

/* Nonzero means current function must be given a frame pointer.
   Set in stmt.c if anything is allocated on the stack there.
   Set in reload1.c if anything is allocated on the stack there.  */

int frame_pointer_needed;

/* Assign unique numbers to labels generated for profiling.  */

int profile_label_no;

/* Length so far allocated in PENDING_BLOCKS.  */

static int max_block_depth;

/* Stack of sequence numbers of symbol-blocks of which we have seen the
   beginning but not yet the end.  Sequence numbers are assigned at
   the beginning; this stack allows us to find the sequence number
   of a block that is ending.  */

static int *pending_blocks;

/* Number of elements currently in use in PENDING_BLOCKS.  */

static int block_depth;

/* Nonzero if have enabled APP processing of our assembler output.  */

static int app_on;

/* If we are outputting an insn sequence, this contains the sequence rtx.
   Zero otherwise.  */

rtx final_sequence;

#ifdef ASSEMBLER_DIALECT

/* Number of the assembler dialect to use, starting at 0.  */
static int dialect_number;
#endif

/* Indexed by line number, nonzero if there is a note for that line.  */

static char *line_note_exists;

/* Linked list to hold line numbers for each basic block.  */

struct bb_list {
  struct bb_list *next;         /* pointer to next basic block */
  int line_num;                 /* line number */
  int file_label_num;           /* LPBC<n> label # for stored filename */
  int func_label_num;           /* LPBC<n> label # for stored function name */
};

static struct bb_list *bb_head  = 0;            /* Head of basic block list */
static struct bb_list **bb_tail = &bb_head;     /* Ptr to store next bb ptr */
static int bb_file_label_num    = -1;           /* Current label # for file */
static int bb_func_label_num    = -1;           /* Current label # for func */

/* Linked list to hold the strings for each file and function name output.  */

struct bb_str {
  struct bb_str *next;          /* pointer to next string */
  const char *string;           /* string */
  int label_num;                /* label number */
  int length;                   /* string length */
};

extern rtx peephole             PROTO((rtx));

static struct bb_str *sbb_head  = 0;            /* Head of string list.  */
static struct bb_str **sbb_tail = &sbb_head;    /* Ptr to store next bb str */
static int sbb_label_num        = 0;            /* Last label used */

#ifdef HAVE_ATTR_length
static int asm_insn_count       PROTO((rtx));
#endif
static void profile_function    PROTO((FILE *));
static void profile_after_prologue PROTO((FILE *));
static void add_bb              PROTO((FILE *));
static int add_bb_string        PROTO((const char *, int));
static void output_source_line  PROTO((FILE *, rtx));
static rtx walk_alter_subreg    PROTO((rtx));
static void output_asm_name     PROTO((void));
static void output_operand      PROTO((rtx, int));
#ifdef LEAF_REGISTERS
static void leaf_renumber_regs  PROTO((rtx));
#endif
#ifdef HAVE_cc0
static int alter_cond           PROTO((rtx));
#endif

extern char *getpwd ();
\f
/* Initialize data in final at the beginning of a compilation.  */

void
init_final (filename)
     char *filename;
{
  next_block_index = 2;
  app_on = 0;
  max_block_depth = 20;
  pending_blocks = (int *) xmalloc (20 * sizeof *pending_blocks);
  final_sequence = 0;

#ifdef ASSEMBLER_DIALECT
  dialect_number = ASSEMBLER_DIALECT;
#endif
}

/* Called at end of source file,
   to output the block-profiling table for this entire compilation.  */

void
end_final (filename)
  const char *filename;
{
  int i;

  if (profile_block_flag || profile_arc_flag)
    {
      char name[20];
      int align = exact_log2 (BIGGEST_ALIGNMENT / BITS_PER_UNIT);
      int size, rounded;
      struct bb_list *ptr;
      struct bb_str *sptr;
      int long_bytes = LONG_TYPE_SIZE / BITS_PER_UNIT;
      int pointer_bytes = POINTER_SIZE / BITS_PER_UNIT;

      if (profile_block_flag)
        size = long_bytes * count_basic_blocks;
      else
        size = long_bytes * count_instrumented_arcs;
      rounded = size;

      rounded += (BIGGEST_ALIGNMENT / BITS_PER_UNIT) - 1;
      rounded = (rounded / (BIGGEST_ALIGNMENT / BITS_PER_UNIT)
                 * (BIGGEST_ALIGNMENT / BITS_PER_UNIT));

      data_section ();

      /* Output the main header, of 11 words:
         0:  1 if this file is initialized, else 0.
         1:  address of file name (LPBX1).
         2:  address of table of counts (LPBX2).
         3:  number of counts in the table.
         4:  always 0, for compatibility with Sun.

         The following are GNU extensions:

         5:  address of table of start addrs of basic blocks (LPBX3).
         6:  Number of bytes in this header.
         7:  address of table of function names (LPBX4).
         8:  address of table of line numbers (LPBX5) or 0.
         9:  address of table of file names (LPBX6) or 0.
        10:  space reserved for basic block profiling.  */

      ASM_OUTPUT_ALIGN (asm_out_file, align);

      ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LPBX", 0);
      /* zero word */
      assemble_integer (const0_rtx, long_bytes, 1);

      /* address of filename */
      ASM_GENERATE_INTERNAL_LABEL (name, "LPBX", 1);
      assemble_integer (gen_rtx_SYMBOL_REF (Pmode, name), pointer_bytes, 1);

      /* address of count table */
      ASM_GENERATE_INTERNAL_LABEL (name, "LPBX", 2);
      assemble_integer (gen_rtx_SYMBOL_REF (Pmode, name), pointer_bytes, 1);

      /* count of the # of basic blocks or # of instrumented arcs */
      if (profile_block_flag)
        assemble_integer (GEN_INT (count_basic_blocks), long_bytes, 1);
      else
        assemble_integer (GEN_INT (count_instrumented_arcs), long_bytes,
                          1);

      /* zero word (link field) */
      assemble_integer (const0_rtx, pointer_bytes, 1);

      /* address of basic block start address table */
      if (profile_block_flag)
        {
          ASM_GENERATE_INTERNAL_LABEL (name, "LPBX", 3);
          assemble_integer (gen_rtx_SYMBOL_REF (Pmode, name), pointer_bytes,
                            1);
        }
      else
        assemble_integer (const0_rtx, pointer_bytes, 1);

      /* byte count for extended structure.  */
      assemble_integer (GEN_INT (11 * UNITS_PER_WORD), long_bytes, 1);

      /* address of function name table */
      if (profile_block_flag)
        {
          ASM_GENERATE_INTERNAL_LABEL (name, "LPBX", 4);
          assemble_integer (gen_rtx_SYMBOL_REF (Pmode, name), pointer_bytes,
                            1);
        }
      else
        assemble_integer (const0_rtx, pointer_bytes, 1);

      /* address of line number and filename tables if debugging.  */
      if (write_symbols != NO_DEBUG && profile_block_flag)
        {
          ASM_GENERATE_INTERNAL_LABEL (name, "LPBX", 5);
          assemble_integer (gen_rtx_SYMBOL_REF (Pmode, name), pointer_bytes, 1);
          ASM_GENERATE_INTERNAL_LABEL (name, "LPBX", 6);
          assemble_integer (gen_rtx_SYMBOL_REF (Pmode, name), pointer_bytes, 1);
        }
      else
        {
          assemble_integer (const0_rtx, pointer_bytes, 1);
          assemble_integer (const0_rtx, pointer_bytes, 1);
        }

      /* space for extension ptr (link field) */
      assemble_integer (const0_rtx, UNITS_PER_WORD, 1);

      /* Output the file name changing the suffix to .d for Sun tcov
         compatibility.  */
      ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LPBX", 1);
      {
        char *cwd = getpwd ();
        int len = strlen (filename) + strlen (cwd) + 1;
        char *data_file = (char *) alloca (len + 4);

        strcpy (data_file, cwd);
        strcat (data_file, "/");
        strcat (data_file, filename);
        strip_off_ending (data_file, len);
        if (profile_block_flag)
          strcat (data_file, ".d");
        else
          strcat (data_file, ".da");
        assemble_string (data_file, strlen (data_file) + 1);
      }

      /* Make space for the table of counts.  */
      if (size == 0)
        {
          /* Realign data section.  */
          ASM_OUTPUT_ALIGN (asm_out_file, align);
          ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LPBX", 2);
          if (size != 0)
            assemble_zeros (size);
        }
      else
        {
          ASM_GENERATE_INTERNAL_LABEL (name, "LPBX", 2);
#ifdef ASM_OUTPUT_SHARED_LOCAL
          if (flag_shared_data)
            ASM_OUTPUT_SHARED_LOCAL (asm_out_file, name, size, rounded);
          else
#endif
#ifdef ASM_OUTPUT_ALIGNED_DECL_LOCAL
            ASM_OUTPUT_ALIGNED_DECL_LOCAL (asm_out_file, NULL_TREE, name, size,
                                              BIGGEST_ALIGNMENT);
#else
#ifdef ASM_OUTPUT_ALIGNED_LOCAL
            ASM_OUTPUT_ALIGNED_LOCAL (asm_out_file, name, size,
                                      BIGGEST_ALIGNMENT);
#else
            ASM_OUTPUT_LOCAL (asm_out_file, name, size, rounded);
#endif
#endif
        }

      /* Output any basic block strings */
      if (profile_block_flag)
        {
          readonly_data_section ();
          if (sbb_head)
            {
              ASM_OUTPUT_ALIGN (asm_out_file, align);
              for (sptr = sbb_head; sptr != 0; sptr = sptr->next)
                {
                  ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LPBC",
                                             sptr->label_num);
                  assemble_string (sptr->string, sptr->length);
                }
            }
        }

      /* Output the table of addresses.  */
      if (profile_block_flag)
        {
          /* Realign in new section */
          ASM_OUTPUT_ALIGN (asm_out_file, align);
          ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LPBX", 3);
          for (i = 0; i < count_basic_blocks; i++)
            {
              ASM_GENERATE_INTERNAL_LABEL (name, "LPB", i);
              assemble_integer (gen_rtx_SYMBOL_REF (Pmode, name),
                                pointer_bytes, 1);
            }
        }

      /* Output the table of function names.  */
      if (profile_block_flag)
        {
          ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LPBX", 4);
          for ((ptr = bb_head), (i = 0); ptr != 0; (ptr = ptr->next), i++)
            {
              if (ptr->func_label_num >= 0)
                {
                  ASM_GENERATE_INTERNAL_LABEL (name, "LPBC",
                                               ptr->func_label_num);
                  assemble_integer (gen_rtx_SYMBOL_REF (Pmode, name),
                                    pointer_bytes, 1);
                }
              else
                assemble_integer (const0_rtx, pointer_bytes, 1);
            }

          for ( ; i < count_basic_blocks; i++)
            assemble_integer (const0_rtx, pointer_bytes, 1);
        }

      if (write_symbols != NO_DEBUG && profile_block_flag)
        {
          /* Output the table of line numbers.  */
          ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LPBX", 5);
          for ((ptr = bb_head), (i = 0); ptr != 0; (ptr = ptr->next), i++)
            assemble_integer (GEN_INT (ptr->line_num), long_bytes, 1);

          for ( ; i < count_basic_blocks; i++)
            assemble_integer (const0_rtx, long_bytes, 1);

          /* Output the table of file names.  */
          ASM_OUTPUT_INTERNAL_LABEL (asm_out_file, "LPBX", 6);
          for ((ptr = bb_head), (i = 0); ptr != 0; (ptr = ptr->next), i++)
            {
              if (ptr->file_label_num >= 0)
                {
                  ASM_GENERATE_INTERNAL_LABEL (name, "LPBC",
                                               ptr->file_label_num);
                  assemble_integer (gen_rtx_SYMBOL_REF (Pmode, name),
                                    pointer_bytes, 1);
                }
              else
                assemble_integer (const0_rtx, pointer_bytes, 1);
            }

          for ( ; i < count_basic_blocks; i++)
            assemble_integer (const0_rtx, pointer_bytes, 1);
        }

      /* End with the address of the table of addresses,
         so we can find it easily, as the last word in the file's text.  */
      if (profile_block_flag)
        {
          ASM_GENERATE_INTERNAL_LABEL (name, "LPBX", 3);
          assemble_integer (gen_rtx_SYMBOL_REF (Pmode, name), pointer_bytes,
                            1);
        }
    }
}

/* Enable APP processing of subsequent output.
   Used before the output from an `asm' statement.  */

void
app_enable ()
{
  if (! app_on)
    {
      fputs (ASM_APP_ON, asm_out_file);
      app_on = 1;
    }
}

/* Disable APP processing of subsequent output.
   Called from varasm.c before most kinds of output.  */

void
app_disable ()
{
  if (app_on)
    {
      fputs (ASM_APP_OFF, asm_out_file);
      app_on = 0;
    }
}
\f
/* Return the number of slots filled in the current 
   delayed branch sequence (we don't count the insn needing the
   delay slot).   Zero if not in a delayed branch sequence.  */

#ifdef DELAY_SLOTS
int
dbr_sequence_length ()
{
  if (final_sequence != 0)
    return XVECLEN (final_sequence, 0) - 1;
  else
    return 0;
}
#endif
\f
/* The next two pages contain routines used to compute the length of an insn
   and to shorten branches.  */

/* Arrays for insn lengths, and addresses.  The latter is referenced by
   `insn_current_length'.  */

static short *insn_lengths;
int *insn_addresses;

/* Max uid for which the above arrays are valid.  */
static int insn_lengths_max_uid;

/* Address of insn being processed.  Used by `insn_current_length'.  */
int insn_current_address;

/* Address of insn being processed in previous iteration.  */
int insn_last_address;

/* konwn invariant alignment of insn being processed.  */
int insn_current_align;

/* After shorten_branches, for any insn, uid_align[INSN_UID (insn)]
   gives the next following alignment insn that increases the known
   alignment, or NULL_RTX if there is no such insn.
   For any alignment obtained this way, we can again index uid_align with
   its uid to obtain the next following align that in turn increases the
   alignment, till we reach NULL_RTX; the sequence obtained this way
   for each insn we'll call the alignment chain of this insn in the following
   comments.  */

struct label_alignment {
  short alignment;
  short max_skip;
};

static rtx *uid_align;
static int *uid_shuid;
static struct label_alignment *label_align;

/* Indicate that branch shortening hasn't yet been done.  */

void
init_insn_lengths ()
{
  if (label_align)
    {
      free (label_align);
      label_align = 0;
    }
  if (uid_shuid)
    {
      free (uid_shuid);
      uid_shuid = 0;
    }
  if (insn_lengths)
    {
      free (insn_lengths);
      insn_lengths = 0;
      insn_lengths_max_uid = 0;
    }
  if (insn_addresses)
    {
      free (insn_addresses);
      insn_addresses = 0;
    }
  if (uid_align)
    {
      free (uid_align);
      uid_align = 0;
    }
}

/* Obtain the current length of an insn.  If branch shortening has been done,
   get its actual length.  Otherwise, get its maximum length.  */

int
get_attr_length (insn)
     rtx insn;
{
#ifdef HAVE_ATTR_length
  rtx body;
  int i;
  int length = 0;

  if (insn_lengths_max_uid > INSN_UID (insn))
    return insn_lengths[INSN_UID (insn)];
  else
    switch (GET_CODE (insn))
      {
      case NOTE:
      case BARRIER:
      case CODE_LABEL:
        return 0;

      case CALL_INSN:
        length = insn_default_length (insn);
        break;

      case JUMP_INSN:
        body = PATTERN (insn);
        if (GET_CODE (body) == ADDR_VEC || GET_CODE (body) == ADDR_DIFF_VEC)
          {
            /* Alignment is machine-dependent and should be handled by
               ADDR_VEC_ALIGN.  */
          }
        else
          length = insn_default_length (insn);
        break;

      case INSN:
        body = PATTERN (insn);
        if (GET_CODE (body) == USE || GET_CODE (body) == CLOBBER)
          return 0;

        else if (GET_CODE (body) == ASM_INPUT || asm_noperands (body) >= 0)
          length = asm_insn_count (body) * insn_default_length (insn);
        else if (GET_CODE (body) == SEQUENCE)
          for (i = 0; i < XVECLEN (body, 0); i++)
            length += get_attr_length (XVECEXP (body, 0, i));
        else
          length = insn_default_length (insn);
        break;

      default:
        break;
      }

#ifdef ADJUST_INSN_LENGTH
  ADJUST_INSN_LENGTH (insn, length);
#endif
  return length;
#else /* not HAVE_ATTR_length */
  return 0;
#endif /* not HAVE_ATTR_length */
}
\f
/* Code to handle alignment inside shorten_branches.  */

/* Here is an explanation how the algorithm in align_fuzz can give
   proper results:

   Call a sequence of instructions beginning with alignment point X
   and continuing until the next alignment point `block X'.  When `X'
   is used in an expression, it means the alignment value of the 
   alignment point.
   
   Call the distance between the start of the first insn of block X, and
   the end of the last insn of block X `IX', for the `inner size of X'.
   This is clearly the sum of the instruction lengths.
   
   Likewise with the next alignment-delimited block following X, which we
   shall call block Y.
   
   Call the distance between the start of the first insn of block X, and
   the start of the first insn of block Y `OX', for the `outer size of X'.
   
   The estimated padding is then OX - IX.
   
   OX can be safely estimated as
   
           if (X >= Y)
                   OX = round_up(IX, Y)
           else
                   OX = round_up(IX, X) + Y - X
   
   Clearly est(IX) >= real(IX), because that only depends on the
   instruction lengths, and those being overestimated is a given.
   
   Clearly round_up(foo, Z) >= round_up(bar, Z) if foo >= bar, so
   we needn't worry about that when thinking about OX.
   
   When X >= Y, the alignment provided by Y adds no uncertainty factor
   for branch ranges starting before X, so we can just round what we have.
   But when X < Y, we don't know anything about the, so to speak,
   `middle bits', so we have to assume the worst when aligning up from an
   address mod X to one mod Y, which is Y - X.  */

#ifndef LABEL_ALIGN
#define LABEL_ALIGN(LABEL) 0
#endif

#ifndef LABEL_ALIGN_MAX_SKIP
#define LABEL_ALIGN_MAX_SKIP 0
#endif

#ifndef LOOP_ALIGN
#define LOOP_ALIGN(LABEL) 0
#endif

#ifndef LOOP_ALIGN_MAX_SKIP
#define LOOP_ALIGN_MAX_SKIP 0
#endif

#ifndef LABEL_ALIGN_AFTER_BARRIER
#define LABEL_ALIGN_AFTER_BARRIER(LABEL) 0
#endif

#ifndef LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP
#define LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP 0
#endif

#ifndef ADDR_VEC_ALIGN
int
final_addr_vec_align (addr_vec)
     rtx addr_vec;
{
  int align = exact_log2 (GET_MODE_SIZE (GET_MODE (PATTERN (addr_vec))));

  if (align > BIGGEST_ALIGNMENT / BITS_PER_UNIT)
    align = BIGGEST_ALIGNMENT / BITS_PER_UNIT;
  return align;

}
#define ADDR_VEC_ALIGN(ADDR_VEC) final_addr_vec_align (ADDR_VEC)
#endif

#ifndef INSN_LENGTH_ALIGNMENT
#define INSN_LENGTH_ALIGNMENT(INSN) length_unit_log
#endif

#define INSN_SHUID(INSN) (uid_shuid[INSN_UID (INSN)])

static int min_labelno, max_labelno;

#define LABEL_TO_ALIGNMENT(LABEL) \
  (label_align[CODE_LABEL_NUMBER (LABEL) - min_labelno].alignment)

#define LABEL_TO_MAX_SKIP(LABEL) \
  (label_align[CODE_LABEL_NUMBER (LABEL) - min_labelno].max_skip)

/* For the benefit of port specific code do this also as a function.  */
int
label_to_alignment (label)
     rtx label;
{
  return LABEL_TO_ALIGNMENT (label);
}

#ifdef HAVE_ATTR_length
/* The differences in addresses
   between a branch and its target might grow or shrink depending on
   the alignment the start insn of the range (the branch for a forward
   branch or the label for a backward branch) starts out on; if these
   differences are used naively, they can even oscillate infinitely.
   We therefore want to compute a 'worst case' address difference that
   is independent of the alignment the start insn of the range end
   up on, and that is at least as large as the actual difference.
   The function align_fuzz calculates the amount we have to add to the
   naively computed difference, by traversing the part of the alignment
   chain of the start insn of the range that is in front of the end insn
   of the range, and considering for each alignment the maximum amount
   that it might contribute to a size increase.

   For casesi tables, we also want to know worst case minimum amounts of
   address difference, in case a machine description wants to introduce
   some common offset that is added to all offsets in a table.
   For this purpose, align_fuzz with a growth argument of 0 comuptes the
   appropriate adjustment.  */


/* Compute the maximum delta by which the difference of the addresses of
   START and END might grow / shrink due to a different address for start
   which changes the size of alignment insns between START and END.
   KNOWN_ALIGN_LOG is the alignment known for START.
   GROWTH should be ~0 if the objective is to compute potential code size
   increase, and 0 if the objective is to compute potential shrink.
   The return value is undefined for any other value of GROWTH.  */
int
align_fuzz (start, end, known_align_log, growth)
     rtx start, end;
     int known_align_log;
     unsigned growth;
{
  int uid = INSN_UID (start);
  rtx align_label;
  int known_align = 1 << known_align_log;
  int end_shuid = INSN_SHUID (end);
  int fuzz = 0;

  for (align_label = uid_align[uid]; align_label; align_label = uid_align[uid])
    {
      int align_addr, new_align;

      uid = INSN_UID (align_label);
      align_addr = insn_addresses[uid] - insn_lengths[uid];
      if (uid_shuid[uid] > end_shuid)
        break;
      known_align_log = LABEL_TO_ALIGNMENT (align_label);
      new_align = 1 << known_align_log;
      if (new_align < known_align)
        continue;
      fuzz += (-align_addr ^ growth) & (new_align - known_align);
      known_align = new_align;
    }
  return fuzz;
}

/* Compute a worst-case reference address of a branch so that it
   can be safely used in the presence of aligned labels.  Since the
   size of the branch itself is unknown, the size of the branch is
   not included in the range.  I.e. for a forward branch, the reference
   address is the end address of the branch as known from the previous
   branch shortening pass, minus a value to account for possible size
   increase due to alignment.  For a backward branch, it is the start
   address of the branch as known from the current pass, plus a value
   to account for possible size increase due to alignment.
   NB.: Therefore, the maximum offset allowed for backward branches needs
   to exclude the branch size.  */
int
insn_current_reference_address (branch)
     rtx branch;
{
  rtx dest;
  rtx seq = NEXT_INSN (PREV_INSN (branch));
  int seq_uid = INSN_UID (seq);
  if (GET_CODE (branch) != JUMP_INSN)
    /* This can happen for example on the PA; the objective is to know the
       offset to address something in front of the start of the function.
       Thus, we can treat it like a backward branch.
       We assume here that FUNCTION_BOUNDARY / BITS_PER_UNIT is larger than
       any alignment we'd encounter, so we skip the call to align_fuzz.  */
    return insn_current_address;
  dest = JUMP_LABEL (branch);
  /* BRANCH has no proper alignment chain set, so use SEQ.  */
  if (INSN_SHUID (branch) < INSN_SHUID (dest))
    {
      /* Forward branch. */
      return (insn_last_address + insn_lengths[seq_uid]
              - align_fuzz (seq, dest, length_unit_log, ~0));
    }
  else
    {
      /* Backward branch. */
      return (insn_current_address
              + align_fuzz (dest, seq, length_unit_log, ~0));
    }
}
#endif /* HAVE_ATTR_length */
\f
/* Make a pass over all insns and compute their actual lengths by shortening
   any branches of variable length if possible.  */

/* Give a default value for the lowest address in a function.  */

#ifndef FIRST_INSN_ADDRESS
#define FIRST_INSN_ADDRESS 0
#endif

/* shorten_branches might be called multiple times:  for example, the SH
   port splits out-of-range conditional branches in MACHINE_DEPENDENT_REORG.
   In order to do this, it needs proper length information, which it obtains
   by calling shorten_branches.  This cannot be collapsed with
   shorten_branches itself into a single pass unless we also want to intergate
   reorg.c, since the branch splitting exposes new instructions with delay
   slots.  */

void
shorten_branches (first)
     rtx first;
{
  rtx insn;
  int max_uid;
  int i;
  int max_log;
  int max_skip;
#ifdef HAVE_ATTR_length
#define MAX_CODE_ALIGN 16
  rtx seq;
  int something_changed = 1;
  char *varying_length;
  rtx body;
  int uid;
  rtx align_tab[MAX_CODE_ALIGN];

  /* In order to make sure that all instructions have valid length info,
     we must split them before we compute the address/length info.  */

  for (insn = NEXT_INSN (first); insn; insn = NEXT_INSN (insn))
    if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
      {
        rtx old = insn;
        /* Don't split the insn if it has been deleted.  */
        if (! INSN_DELETED_P (old))
          insn = try_split (PATTERN (old), old, 1);
        /* When not optimizing, the old insn will be still left around
           with only the 'deleted' bit set.  Transform it into a note
           to avoid confusion of subsequent processing.  */
        if (INSN_DELETED_P (old))
          {
            PUT_CODE (old , NOTE);
            NOTE_LINE_NUMBER (old) = NOTE_INSN_DELETED;
            NOTE_SOURCE_FILE (old) = 0;
          }
      }
#endif

  /* We must do some computations even when not actually shortening, in
     order to get the alignment information for the labels.  */

  init_insn_lengths ();

  /* Compute maximum UID and allocate label_align / uid_shuid.  */
  max_uid = get_max_uid ();

  max_labelno = max_label_num ();
  min_labelno = get_first_label_num ();
  label_align = (struct label_alignment *) xmalloc (
    (max_labelno - min_labelno + 1) * sizeof (struct label_alignment));
  bzero ((char *) label_align,
    (max_labelno - min_labelno + 1) * sizeof (struct label_alignment));

  uid_shuid = (int *) xmalloc (max_uid * sizeof *uid_shuid);

  /* Initialize label_align and set up uid_shuid to be strictly
     monotonically rising with insn order.  */
  /* We use max_log here to keep track of the maximum alignment we want to
     impose on the next CODE_LABEL (or the current one if we are processing
     the CODE_LABEL itself).  */
     
  max_log = 0;
  max_skip = 0;

  for (insn = get_insns (), i = 1; insn; insn = NEXT_INSN (insn))
    {
      int log;

      INSN_SHUID (insn) = i++;
      if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
        {
          /* reorg might make the first insn of a loop being run once only,
             and delete the label in front of it.  Then we want to apply
             the loop alignment to the new label created by reorg, which
             is separated by the former loop start insn from the
             NOTE_INSN_LOOP_BEG.  */
        }
      else if (GET_CODE (insn) == CODE_LABEL)
        {
          rtx next;

          log = LABEL_ALIGN (insn);
          if (max_log < log)
            {
              max_log = log;
              max_skip = LABEL_ALIGN_MAX_SKIP;
            }
          next = NEXT_INSN (insn);
          /* ADDR_VECs only take room if read-only data goes into the text
             section.  */
          if (JUMP_TABLES_IN_TEXT_SECTION
#if !defined(READONLY_DATA_SECTION)
              || 1
#endif
              )
            if (next && GET_CODE (next) == JUMP_INSN)
              {
                rtx nextbody = PATTERN (next);
                if (GET_CODE (nextbody) == ADDR_VEC
                    || GET_CODE (nextbody) == ADDR_DIFF_VEC)
                  {
                    log = ADDR_VEC_ALIGN (next);
                    if (max_log < log)
                      {
                        max_log = log;
                        max_skip = LABEL_ALIGN_MAX_SKIP;
                      }
                  }
              }
          LABEL_TO_ALIGNMENT (insn) = max_log;
          LABEL_TO_MAX_SKIP (insn) = max_skip;
          max_log = 0;
          max_skip = 0;
        }
      else if (GET_CODE (insn) == BARRIER)
        {
          rtx label;

          for (label = insn; label && GET_RTX_CLASS (GET_CODE (label)) != 'i';
               label = NEXT_INSN (label))
            if (GET_CODE (label) == CODE_LABEL)
              {
                log = LABEL_ALIGN_AFTER_BARRIER (insn);
                if (max_log < log)
                  {
                    max_log = log;
                    max_skip = LABEL_ALIGN_AFTER_BARRIER_MAX_SKIP;
                  }
                break;
              }
        }
      /* Again, we allow NOTE_INSN_LOOP_BEG - INSN - CODE_LABEL
         sequences in order to handle reorg output efficiently.  */
      else if (GET_CODE (insn) == NOTE
               && NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
        {
          rtx label;

          for (label = insn; label; label = NEXT_INSN (label))
            if (GET_CODE (label) == CODE_LABEL)
              {
                log = LOOP_ALIGN (insn);
                if (max_log < log)
                  {
                    max_log = log;
                    max_skip = LOOP_ALIGN_MAX_SKIP;
                  }
                break;
              }
        }
      else
        continue;
    }
#ifdef HAVE_ATTR_length

  /* Allocate the rest of the arrays.  */
  insn_lengths = (short *) xmalloc (max_uid * sizeof (short));
  insn_addresses = (int *) xmalloc (max_uid * sizeof (int));
  insn_lengths_max_uid = max_uid;
  /* Syntax errors can lead to labels being outside of the main insn stream.
     Initialize insn_addresses, so that we get reproducible results.  */
  bzero ((char *)insn_addresses, max_uid * sizeof *insn_addresses);
  uid_align = (rtx *) xmalloc (max_uid * sizeof *uid_align);

  varying_length = (char *) xmalloc (max_uid * sizeof (char));

  bzero (varying_length, max_uid);

  /* Initialize uid_align.  We scan instructions
     from end to start, and keep in align_tab[n] the last seen insn
     that does an alignment of at least n+1, i.e. the successor
     in the alignment chain for an insn that does / has a known
     alignment of n.  */

  bzero ((char *) uid_align, max_uid * sizeof *uid_align);

  for (i = MAX_CODE_ALIGN; --i >= 0; )
    align_tab[i] = NULL_RTX;
  seq = get_last_insn ();
  for (; seq; seq = PREV_INSN (seq))
    {
      int uid = INSN_UID (seq);
      int log;
      log = (GET_CODE (seq) == CODE_LABEL ? LABEL_TO_ALIGNMENT (seq) : 0);
      uid_align[uid] = align_tab[0];
      if (log)
        {
          /* Found an alignment label.  */
          uid_align[uid] = align_tab[log];
          for (i = log - 1; i >= 0; i--)
            align_tab[i] = seq;
        }
    }
#ifdef CASE_VECTOR_SHORTEN_MODE
  if (optimize)
    {
      /* Look for ADDR_DIFF_VECs, and initialize their minimum and maximum
         label fields.  */

      int min_shuid = INSN_SHUID (get_insns ()) - 1;
      int max_shuid = INSN_SHUID (get_last_insn ()) + 1;
      int rel;

      for (insn = first; insn != 0; insn = NEXT_INSN (insn))
        {
          rtx min_lab = NULL_RTX, max_lab = NULL_RTX, pat;
          int len, i, min, max, insn_shuid;
          int min_align;
          addr_diff_vec_flags flags;

          if (GET_CODE (insn) != JUMP_INSN
              || GET_CODE (PATTERN (insn)) != ADDR_DIFF_VEC)
            continue;
          pat = PATTERN (insn);
          len = XVECLEN (pat, 1);
          if (len <= 0)
            abort ();
          min_align = MAX_CODE_ALIGN;
          for (min = max_shuid, max = min_shuid, i = len - 1; i >= 0; i--)
            {
              rtx lab = XEXP (XVECEXP (pat, 1, i), 0);
              int shuid = INSN_SHUID (lab);
              if (shuid < min)
                {
                  min = shuid;
                  min_lab = lab;
                }
              if (shuid > max)
                {
                  max = shuid;
                  max_lab = lab;
                }
              if (min_align > LABEL_TO_ALIGNMENT (lab))
                min_align = LABEL_TO_ALIGNMENT (lab);
            }
          XEXP (pat, 2) = gen_rtx_LABEL_REF (VOIDmode, min_lab);
          XEXP (pat, 3) = gen_rtx_LABEL_REF (VOIDmode, max_lab);
          insn_shuid = INSN_SHUID (insn);
          rel = INSN_SHUID (XEXP (XEXP (pat, 0), 0));
          flags.min_align = min_align;
          flags.base_after_vec = rel > insn_shuid;
          flags.min_after_vec  = min > insn_shuid;
          flags.max_after_vec  = max > insn_shuid;
          flags.min_after_base = min > rel;
          flags.max_after_base = max > rel;
          ADDR_DIFF_VEC_FLAGS (pat) = flags;
        }
    }
#endif /* CASE_VECTOR_SHORTEN_MODE */


  /* Compute initial lengths, addresses, and varying flags for each insn.  */
  for (insn_current_address = FIRST_INSN_ADDRESS, insn = first;
       insn != 0;
       insn_current_address += insn_lengths[uid], insn = NEXT_INSN (insn))
    {
      uid = INSN_UID (insn);

      insn_lengths[uid] = 0;

      if (GET_CODE (insn) == CODE_LABEL)
        {
          int log = LABEL_TO_ALIGNMENT (insn);
          if (log)
            {
              int align = 1 << log;
              int new_address = (insn_current_address + align - 1) & -align;
              insn_lengths[uid] = new_address - insn_current_address;
              insn_current_address = new_address;
            }
        }

      insn_addresses[uid] = insn_current_address;
      
      if (GET_CODE (insn) == NOTE || GET_CODE (insn) == BARRIER
          || GET_CODE (insn) == CODE_LABEL)
        continue;
      if (INSN_DELETED_P (insn))
        continue;

      body = PATTERN (insn);
      if (GET_CODE (body) == ADDR_VEC || GET_CODE (body) == ADDR_DIFF_VEC)
        {
          /* This only takes room if read-only data goes into the text
             section.  */
          if (JUMP_TABLES_IN_TEXT_SECTION
#if !defined(READONLY_DATA_SECTION)
              || 1
#endif
              )
            insn_lengths[uid] = (XVECLEN (body,
                                          GET_CODE (body) == ADDR_DIFF_VEC)
                                 * GET_MODE_SIZE (GET_MODE (body)));
          /* Alignment is handled by ADDR_VEC_ALIGN.  */
        }
      else if (asm_noperands (body) >= 0)
        insn_lengths[uid] = asm_insn_count (body) * insn_default_length (insn);
      else if (GET_CODE (body) == SEQUENCE)
        {
          int i;
          int const_delay_slots;
#ifdef DELAY_SLOTS
          const_delay_slots = const_num_delay_slots (XVECEXP (body, 0, 0));
#else
          const_delay_slots = 0;
#endif
          /* Inside a delay slot sequence, we do not do any branch shortening
             if the shortening could change the number of delay slots
             of the branch.  */
          for (i = 0; i < XVECLEN (body, 0); i++)
            {
              rtx inner_insn = XVECEXP (body, 0, i);
              int inner_uid = INSN_UID (inner_insn);
              int inner_length;

              if (asm_noperands (PATTERN (XVECEXP (body, 0, i))) >= 0)
                inner_length = (asm_insn_count (PATTERN (inner_insn))
                                * insn_default_length (inner_insn));
              else
                inner_length = insn_default_length (inner_insn);
              
              insn_lengths[inner_uid] = inner_length;
              if (const_delay_slots)
                {
                  if ((varying_length[inner_uid]
                       = insn_variable_length_p (inner_insn)) != 0)
                    varying_length[uid] = 1;
                  insn_addresses[inner_uid] = (insn_current_address +
                                               insn_lengths[uid]);
                }
              else
                varying_length[inner_uid] = 0;
              insn_lengths[uid] += inner_length;
            }
        }
      else if (GET_CODE (body) != USE && GET_CODE (body) != CLOBBER)
        {
          insn_lengths[uid] = insn_default_length (insn);
          varying_length[uid] = insn_variable_length_p (insn);
        }

      /* If needed, do any adjustment.  */
#ifdef ADJUST_INSN_LENGTH
      ADJUST_INSN_LENGTH (insn, insn_lengths[uid]);
      if (insn_lengths[uid] < 0)
        fatal_insn ("Negative insn length", insn);
#endif
    }

  /* Now loop over all the insns finding varying length insns.  For each,
     get the current insn length.  If it has changed, reflect the change.
     When nothing changes for a full pass, we are done.  */

  while (something_changed)
    {
      something_changed = 0;
      insn_current_align = MAX_CODE_ALIGN - 1;
      for (insn_current_address = FIRST_INSN_ADDRESS, insn = first;
           insn != 0;
           insn = NEXT_INSN (insn))
        {
          int new_length;
#ifdef ADJUST_INSN_LENGTH
          int tmp_length;
#endif
          int length_align;

          uid = INSN_UID (insn);

          if (GET_CODE (insn) == CODE_LABEL)
            {
              int log = LABEL_TO_ALIGNMENT (insn);
              if (log > insn_current_align)
                {
                  int align = 1 << log;
                  int new_address= (insn_current_address + align - 1) & -align;
                  insn_lengths[uid] = new_address - insn_current_address;
                  insn_current_align = log;
                  insn_current_address = new_address;
                }
              else
                insn_lengths[uid] = 0;
              insn_addresses[uid] = insn_current_address;
              continue;
            }

          length_align = INSN_LENGTH_ALIGNMENT (insn);
          if (length_align < insn_current_align)
            insn_current_align = length_align;

          insn_last_address = insn_addresses[uid];
          insn_addresses[uid] = insn_current_address;

#ifdef CASE_VECTOR_SHORTEN_MODE
          if (optimize && GET_CODE (insn) == JUMP_INSN
              && GET_CODE (PATTERN (insn)) == ADDR_DIFF_VEC)
            {
              rtx body = PATTERN (insn);
              int old_length = insn_lengths[uid];
              rtx rel_lab = XEXP (XEXP (body, 0), 0);
              rtx min_lab = XEXP (XEXP (body, 2), 0);
              rtx max_lab = XEXP (XEXP (body, 3), 0);
              addr_diff_vec_flags flags = ADDR_DIFF_VEC_FLAGS (body);
              int rel_addr = insn_addresses[INSN_UID (rel_lab)];
              int min_addr = insn_addresses[INSN_UID (min_lab)];
              int max_addr = insn_addresses[INSN_UID (max_lab)];
              rtx prev;
              int rel_align = 0;

              /* Try to find a known alignment for rel_lab.  */
              for (prev = rel_lab;
                   prev
                   && ! insn_lengths[INSN_UID (prev)]
                   && ! (varying_length[INSN_UID (prev)] & 1);
                   prev = PREV_INSN (prev))
                if (varying_length[INSN_UID (prev)] & 2)
                  {
                    rel_align = LABEL_TO_ALIGNMENT (prev);
                    break;
                  }

              /* See the comment on addr_diff_vec_flags in rtl.h for the
                 meaning of the flags values.  base: REL_LAB   vec: INSN  */
              /* Anything after INSN has still addresses from the last
                 pass; adjust these so that they reflect our current
                 estimate for this pass.  */
              if (flags.base_after_vec)
                rel_addr += insn_current_address - insn_last_address;
              if (flags.min_after_vec)
                min_addr += insn_current_address - insn_last_address;
              if (flags.max_after_vec)
                max_addr += insn_current_address - insn_last_address;
              /* We want to know the worst case, i.e. lowest possible value
                 for the offset of MIN_LAB.  If MIN_LAB is after REL_LAB,
                 its offset is positive, and we have to be wary of code shrink;
                 otherwise, it is negative, and we have to be vary of code
                 size increase.  */
              if (flags.min_after_base)
                {
                  /* If INSN is between REL_LAB and MIN_LAB, the size
                     changes we are about to make can change the alignment
                     within the observed offset, therefore we have to break
                     it up into two parts that are independent.  */
                  if (! flags.base_after_vec && flags.min_after_vec)
                    {
                      min_addr -= align_fuzz (rel_lab, insn, rel_align, 0);
                      min_addr -= align_fuzz (insn, min_lab, 0, 0);
                    }
                  else
                    min_addr -= align_fuzz (rel_lab, min_lab, rel_align, 0);
                }
              else
                {
                  if (flags.base_after_vec && ! flags.min_after_vec)
                    {
                      min_addr -= align_fuzz (min_lab, insn, 0, ~0);
                      min_addr -= align_fuzz (insn, rel_lab, 0, ~0);
                    }
                  else
                    min_addr -= align_fuzz (min_lab, rel_lab, 0, ~0);
                }
              /* Likewise, determine the highest lowest possible value
                 for the offset of MAX_LAB.  */
              if (flags.max_after_base)
                {
                  if (! flags.base_after_vec && flags.max_after_vec)
                    {
                      max_addr += align_fuzz (rel_lab, insn, rel_align, ~0);
                      max_addr += align_fuzz (insn, max_lab, 0, ~0);
                    }
                  else
                    max_addr += align_fuzz (rel_lab, max_lab, rel_align, ~0);
                }
              else
                {
                  if (flags.base_after_vec && ! flags.max_after_vec)
                    {
                      max_addr += align_fuzz (max_lab, insn, 0, 0);
                      max_addr += align_fuzz (insn, rel_lab, 0, 0);
                    }
                  else
                    max_addr += align_fuzz (max_lab, rel_lab, 0, 0);
                }
              PUT_MODE (body, CASE_VECTOR_SHORTEN_MODE (min_addr - rel_addr,
                                                        max_addr - rel_addr,
                                                        body));
              if (JUMP_TABLES_IN_TEXT_SECTION
#if !defined(READONLY_DATA_SECTION)
                  || 1
#endif
                  )
                {
                  insn_lengths[uid]
                    = (XVECLEN (body, 1) * GET_MODE_SIZE (GET_MODE (body)));
                  insn_current_address += insn_lengths[uid];
                  if (insn_lengths[uid] != old_length)
                    something_changed = 1;
                }

              continue;
            }
#endif /* CASE_VECTOR_SHORTEN_MODE */

          if (! (varying_length[uid]))
            {
              insn_current_address += insn_lengths[uid];
              continue;
            }
          if (GET_CODE (insn) == INSN && GET_CODE (PATTERN (insn)) == SEQUENCE)
            {
              int i;
              
              body = PATTERN (insn);
              new_length = 0;
              for (i = 0; i < XVECLEN (body, 0); i++)
                {
                  rtx inner_insn = XVECEXP (body, 0, i);
                  int inner_uid = INSN_UID (inner_insn);
                  int inner_length;

                  insn_addresses[inner_uid] = insn_current_address;

                  /* insn_current_length returns 0 for insns with a
                     non-varying length.  */
                  if (! varying_length[inner_uid])
                    inner_length = insn_lengths[inner_uid];
                  else
                    inner_length = insn_current_length (inner_insn);

                  if (inner_length != insn_lengths[inner_uid])
                    {
                      insn_lengths[inner_uid] = inner_length;
                      something_changed = 1;
                    }
                  insn_current_address += insn_lengths[inner_uid];
                  new_length += inner_length;
                }
            }
          else
            {
              new_length = insn_current_length (insn);
              insn_current_address += new_length;
            }

#ifdef ADJUST_INSN_LENGTH
          /* If needed, do any adjustment.  */
          tmp_length = new_length;
          ADJUST_INSN_LENGTH (insn, new_length);
          insn_current_address += (new_length - tmp_length);
#endif

          if (new_length != insn_lengths[uid])
            {
              insn_lengths[uid] = new_length;
              something_changed = 1;
            }
        }
      /* For a non-optimizing compile, do only a single pass.  */
      if (!optimize)
        break;
    }

  free (varying_length);

#endif /* HAVE_ATTR_length */
}

#ifdef HAVE_ATTR_length
/* Given the body of an INSN known to be generated by an ASM statement, return
   the number of machine instructions likely to be generated for this insn.
   This is used to compute its length.  */

static int
asm_insn_count (body)
     rtx body;
{
  char *template;
  int count = 1;

  if (GET_CODE (body) == ASM_INPUT)
    template = XSTR (body, 0);
  else
    template = decode_asm_operands (body, NULL_PTR, NULL_PTR,
                                    NULL_PTR, NULL_PTR);

  for ( ; *template; template++)
    if (IS_ASM_LOGICAL_LINE_SEPARATOR(*template) || *template == '\n')
      count++;

  return count;
}
#endif
\f
/* Output assembler code for the start of a function,
   and initialize some of the variables in this file
   for the new function.  The label for the function and associated
   assembler pseudo-ops have already been output in `assemble_start_function'.

   FIRST is the first insn of the rtl for the function being compiled.
   FILE is the file to write assembler code to.
   OPTIMIZE is nonzero if we should eliminate redundant
     test and compare insns.  */

void
final_start_function (first, file, optimize)
     rtx first;
     FILE *file;
     int optimize;
{
  block_depth = 0;

  this_is_asm_operands = 0;

#ifdef NON_SAVING_SETJMP
  /* A function that calls setjmp should save and restore all the
     call-saved registers on a system where longjmp clobbers them.  */
  if (NON_SAVING_SETJMP && current_function_calls_setjmp)
    {
      int i;

      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
        if (!call_used_regs[i])
          regs_ever_live[i] = 1;
    }
#endif
  
  /* Initial line number is supposed to be output
     before the function's prologue and label
     so that the function's address will not appear to be
     in the last statement of the preceding function.  */
  if (NOTE_LINE_NUMBER (first) != NOTE_INSN_DELETED)
    last_linenum = high_block_linenum = high_function_linenum
      = NOTE_LINE_NUMBER (first);

#if defined (DWARF2_UNWIND_INFO) || defined (DWARF2_DEBUGGING_INFO)
  /* Output DWARF definition of the function.  */
  if (dwarf2out_do_frame ())
    dwarf2out_begin_prologue ();
#endif

  /* For SDB and XCOFF, the function beginning must be marked between
     the function label and the prologue.  We always need this, even when
     -g1 was used.  Defer on MIPS systems so that parameter descriptions
     follow function entry.  */
#if defined(SDB_DEBUGGING_INFO) && !defined(MIPS_DEBUGGING_INFO)
  if (write_symbols == SDB_DEBUG)
    sdbout_begin_function (last_linenum);
  else
#endif
#ifdef XCOFF_DEBUGGING_INFO
    if (write_symbols == XCOFF_DEBUG)
      xcoffout_begin_function (file, last_linenum);
    else
#endif    
      /* But only output line number for other debug info types if -g2
         or better.  */
      if (NOTE_LINE_NUMBER (first) != NOTE_INSN_DELETED)
        output_source_line (file, first);

#ifdef LEAF_REG_REMAP
  if (current_function_uses_only_leaf_regs)
    leaf_renumber_regs (first);
#endif

  if (profile_block_flag)
    add_bb (file);

  /* The Sun386i and perhaps other machines don't work right
     if the profiling code comes after the prologue.  */
#ifdef PROFILE_BEFORE_PROLOGUE
  if (profile_flag)
    profile_function (file);
#endif /* PROFILE_BEFORE_PROLOGUE */

#if defined (DWARF2_UNWIND_INFO) && defined (HAVE_prologue)
  if (dwarf2out_do_frame ())
    dwarf2out_frame_debug (NULL_RTX);
#endif

#ifdef FUNCTION_PROLOGUE
  /* First output the function prologue: code to set up the stack frame.  */
  FUNCTION_PROLOGUE (file, get_frame_size ());
#endif

#if defined (SDB_DEBUGGING_INFO) || defined (XCOFF_DEBUGGING_INFO)
  if (write_symbols == SDB_DEBUG || write_symbols == XCOFF_DEBUG)
    next_block_index = 1;
#endif

  /* If the machine represents the prologue as RTL, the profiling code must
     be emitted when NOTE_INSN_PROLOGUE_END is scanned.  */
#ifdef HAVE_prologue
  if (! HAVE_prologue)
#endif
    profile_after_prologue (file);

  profile_label_no++;

  /* If we are doing basic block profiling, remember a printable version
     of the function name.  */
  if (profile_block_flag)
    {
      bb_func_label_num
        = add_bb_string ((*decl_printable_name) (current_function_decl, 2), FALSE);
    }
}

static void
profile_after_prologue (file)
     FILE *file;
{
#ifdef FUNCTION_BLOCK_PROFILER
  if (profile_block_flag)
    {
      FUNCTION_BLOCK_PROFILER (file, count_basic_blocks);
    }
#endif /* FUNCTION_BLOCK_PROFILER */

#ifndef PROFILE_BEFORE_PROLOGUE
  if (profile_flag)
    profile_function (file);
#endif /* not PROFILE_BEFORE_PROLOGUE */
}

static void
profile_function (file)
     FILE *file;
{
#ifndef NO_PROFILE_COUNTERS
  int align = MIN (BIGGEST_ALIGNMENT, LONG_TYPE_SIZE);
#endif
#if defined(ASM_OUTPUT_REG_PUSH)
#if defined(STRUCT_VALUE_INCOMING_REGNUM) || defined(STRUCT_VALUE_REGNUM)
  int sval = current_function_returns_struct;
#endif
#if defined(STATIC_CHAIN_INCOMING_REGNUM) || defined(STATIC_CHAIN_REGNUM)
  int cxt = current_function_needs_context;
#endif
#endif /* ASM_OUTPUT_REG_PUSH */

#ifndef NO_PROFILE_COUNTERS
  data_section ();
  ASM_OUTPUT_ALIGN (file, floor_log2 (align / BITS_PER_UNIT));
  ASM_OUTPUT_INTERNAL_LABEL (file, "LP", profile_label_no);
  assemble_integer (const0_rtx, LONG_TYPE_SIZE / BITS_PER_UNIT, 1);
#endif

  function_section (current_function_decl);

#if defined(STRUCT_VALUE_INCOMING_REGNUM) && defined(ASM_OUTPUT_REG_PUSH)
  if (sval)
    ASM_OUTPUT_REG_PUSH (file, STRUCT_VALUE_INCOMING_REGNUM);
#else
#if defined(STRUCT_VALUE_REGNUM) && defined(ASM_OUTPUT_REG_PUSH)
  if (sval)
    {
      ASM_OUTPUT_REG_PUSH (file, STRUCT_VALUE_REGNUM);
    }
#endif
#endif

#if defined(STATIC_CHAIN_INCOMING_REGNUM) && defined(ASM_OUTPUT_REG_PUSH)
  if (cxt)
    ASM_OUTPUT_REG_PUSH (file, STATIC_CHAIN_INCOMING_REGNUM);
#else
#if defined(STATIC_CHAIN_REGNUM) && defined(ASM_OUTPUT_REG_PUSH)
  if (cxt)
    {
      ASM_OUTPUT_REG_PUSH (file, STATIC_CHAIN_REGNUM);
    }
#endif
#endif

  FUNCTION_PROFILER (file, profile_label_no);

#if defined(STATIC_CHAIN_INCOMING_REGNUM) && defined(ASM_OUTPUT_REG_PUSH)
  if (cxt)
    ASM_OUTPUT_REG_POP (file, STATIC_CHAIN_INCOMING_REGNUM);
#else
#if defined(STATIC_CHAIN_REGNUM) && defined(ASM_OUTPUT_REG_PUSH)
  if (cxt)
    {
      ASM_OUTPUT_REG_POP (file, STATIC_CHAIN_REGNUM);
    }
#endif
#endif

#if defined(STRUCT_VALUE_INCOMING_REGNUM) && defined(ASM_OUTPUT_REG_PUSH)
  if (sval)
    ASM_OUTPUT_REG_POP (file, STRUCT_VALUE_INCOMING_REGNUM);
#else
#if defined(STRUCT_VALUE_REGNUM) && defined(ASM_OUTPUT_REG_PUSH)
  if (sval)
    {
      ASM_OUTPUT_REG_POP (file, STRUCT_VALUE_REGNUM);
    }
#endif
#endif
}

/* Output assembler code for the end of a function.
   For clarity, args are same as those of `final_start_function'
   even though not all of them are needed.  */

void
final_end_function (first, file, optimize)
     rtx first;
     FILE *file;
     int optimize;
{
  if (app_on)
    {
      fputs (ASM_APP_OFF, file);
      app_on = 0;
    }

#ifdef SDB_DEBUGGING_INFO
  if (write_symbols == SDB_DEBUG)
    sdbout_end_function (high_function_linenum);
#endif

#ifdef DWARF_DEBUGGING_INFO
  if (write_symbols == DWARF_DEBUG)
    dwarfout_end_function ();
#endif

#ifdef XCOFF_DEBUGGING_INFO
  if (write_symbols == XCOFF_DEBUG)
    xcoffout_end_function (file, high_function_linenum);
#endif

#ifdef FUNCTION_EPILOGUE
  /* Finally, output the function epilogue:
     code to restore the stack frame and return to the caller.  */
  FUNCTION_EPILOGUE (file, get_frame_size ());
#endif

  if (profile_block_flag)
    add_bb (file);

#ifdef SDB_DEBUGGING_INFO
  if (write_symbols == SDB_DEBUG)
    sdbout_end_epilogue ();
#endif

#ifdef DWARF_DEBUGGING_INFO
  if (write_symbols == DWARF_DEBUG)
    dwarfout_end_epilogue ();
#endif

#if defined (DWARF2_UNWIND_INFO) || defined (DWARF2_DEBUGGING_INFO)
  if (dwarf2out_do_frame ())
    dwarf2out_end_epilogue ();
#endif

#ifdef XCOFF_DEBUGGING_INFO
  if (write_symbols == XCOFF_DEBUG)
    xcoffout_end_epilogue (file);
#endif

  bb_func_label_num = -1;       /* not in function, nuke label # */

  /* If FUNCTION_EPILOGUE is not defined, then the function body
     itself contains return instructions wherever needed.  */
}
\f
/* Add a block to the linked list that remembers the current line/file/function
   for basic block profiling.  Emit the label in front of the basic block and
   the instructions that increment the count field.  */

static void
add_bb (file)
     FILE *file;
{
  struct bb_list *ptr = (struct bb_list *) permalloc (sizeof (struct bb_list));

  /* Add basic block to linked list.  */
  ptr->next = 0;
  ptr->line_num = last_linenum;
  ptr->file_label_num = bb_file_label_num;
  ptr->func_label_num = bb_func_label_num;
  *bb_tail = ptr;
  bb_tail = &ptr->next;

  /* Enable the table of basic-block use counts
     to point at the code it applies to.  */
  ASM_OUTPUT_INTERNAL_LABEL (file, "LPB", count_basic_blocks);

  /* Before first insn of this basic block, increment the
     count of times it was entered.  */
#ifdef BLOCK_PROFILER
  BLOCK_PROFILER (file, count_basic_blocks);
#endif
#ifdef HAVE_cc0
  CC_STATUS_INIT;
#endif

  new_block = 0;
  count_basic_blocks++;
}

/* Add a string to be used for basic block profiling.  */

static int
add_bb_string (string, perm_p)
     const char *string;
     int perm_p;
{
  int len;
  struct bb_str *ptr = 0;

  if (!string)
    {
      string = "<unknown>";
      perm_p = TRUE;
    }

  /* Allocate a new string if the current string isn't permanent.  If
     the string is permanent search for the same string in other
     allocations.  */

  len = strlen (string) + 1;
  if (!perm_p)
    {
      char *p = (char *) permalloc (len);
      bcopy (string, p, len);
      string = p;
    }
  else
    for (ptr = sbb_head; ptr != (struct bb_str *) 0; ptr = ptr->next)
      if (ptr->string == string)
        break;

  /* Allocate a new string block if we need to.  */
  if (!ptr)
    {
      ptr = (struct bb_str *) permalloc (sizeof (*ptr));
      ptr->next = 0;
      ptr->length = len;
      ptr->label_num = sbb_label_num++;
      ptr->string = string;
      *sbb_tail = ptr;
      sbb_tail = &ptr->next;
    }

  return ptr->label_num;
}

\f
/* Output assembler code for some insns: all or part of a function.
   For description of args, see `final_start_function', above.

   PRESCAN is 1 if we are not really outputting,
     just scanning as if we were outputting.
   Prescanning deletes and rearranges insns just like ordinary output.
   PRESCAN is -2 if we are outputting after having prescanned.
   In this case, don't try to delete or rearrange insns
   because that has already been done.
   Prescanning is done only on certain machines.  */

void
final (first, file, optimize, prescan)
     rtx first;
     FILE *file;
     int optimize;
     int prescan;
{
  register rtx insn;
  int max_line = 0;
  int max_uid = 0;

  last_ignored_compare = 0;
  new_block = 1;

  check_exception_handler_labels ();

  /* Make a map indicating which line numbers appear in this function.
     When producing SDB debugging info, delete troublesome line number
     notes from inlined functions in other files as well as duplicate
     line number notes.  */
#ifdef SDB_DEBUGGING_INFO
  if (write_symbols == SDB_DEBUG)
    {
      rtx last = 0;
      for (insn = first; insn; insn = NEXT_INSN (insn))
        if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) > 0)
          {
            if ((RTX_INTEGRATED_P (insn)
                 && strcmp (NOTE_SOURCE_FILE (insn), main_input_filename) != 0)
                 || (last != 0
                     && NOTE_LINE_NUMBER (insn) == NOTE_LINE_NUMBER (last)
                     && NOTE_SOURCE_FILE (insn) == NOTE_SOURCE_FILE (last)))
              {
                NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
                NOTE_SOURCE_FILE (insn) = 0;
                continue;
              }
            last = insn;
            if (NOTE_LINE_NUMBER (insn) > max_line)
              max_line = NOTE_LINE_NUMBER (insn);
          }
    }
  else
#endif
    {
      for (insn = first; insn; insn = NEXT_INSN (insn))
        if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) > max_line)
          max_line = NOTE_LINE_NUMBER (insn);
    }

  line_note_exists = (char *) oballoc (max_line + 1);
  bzero (line_note_exists, max_line + 1);

  for (insn = first; insn; insn = NEXT_INSN (insn))
    {
      if (INSN_UID (insn) > max_uid)       /* find largest UID */
        max_uid = INSN_UID (insn);
      if (GET_CODE (insn) == NOTE && NOTE_LINE_NUMBER (insn) > 0)
        line_note_exists[NOTE_LINE_NUMBER (insn)] = 1;
#ifdef HAVE_cc0
      /* If CC tracking across branches is enabled, record the insn which
         jumps to each branch only reached from one place.  */
      if (optimize && GET_CODE (insn) == JUMP_INSN)
        {
          rtx lab = JUMP_LABEL (insn);
          if (lab && LABEL_NUSES (lab) == 1)
            {
              LABEL_REFS (lab) = insn;
            }
        }
#endif
    }

  /* Initialize insn_eh_region table if eh is being used. */
  
  init_insn_eh_region (first, max_uid);

  init_recog ();

  CC_STATUS_INIT;

  /* Output the insns.  */
  for (insn = NEXT_INSN (first); insn;)
    {
#ifdef HAVE_ATTR_length
      insn_current_address = insn_addresses[INSN_UID (insn)];
#endif
      insn = final_scan_insn (insn, file, optimize, prescan, 0);
    }

  /* Do basic-block profiling here
     if the last insn was a conditional branch.  */
  if (profile_block_flag && new_block)
    add_bb (file);

  free_insn_eh_region ();
}
\f
/* The final scan for one insn, INSN.
   Args are same as in `final', except that INSN
   is the insn being scanned.
   Value returned is the next insn to be scanned.

   NOPEEPHOLES is the flag to disallow peephole processing (currently
   used for within delayed branch sequence output).  */

rtx
final_scan_insn (insn, file, optimize, prescan, nopeepholes)
     rtx insn;
     FILE *file;
     int optimize;
     int prescan;
     int nopeepholes;
{
#ifdef HAVE_cc0
  rtx set;
#endif

  insn_counter++;

  /* Ignore deleted insns.  These can occur when we split insns (due to a
     template of "#") while not optimizing.  */
  if (INSN_DELETED_P (insn))
    return NEXT_INSN (insn);

  switch (GET_CODE (insn))
    {
    case NOTE:
      if (prescan > 0)
        break;

      /* Align the beginning of a loop, for higher speed
         on certain machines.  */

      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
        break; /* This used to depend on optimize, but that was bogus.  */
      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END)
        break;

      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG
          && ! exceptions_via_longjmp)
        {
          ASM_OUTPUT_INTERNAL_LABEL (file, "LEHB", NOTE_BLOCK_NUMBER (insn));
          if (! flag_new_exceptions)
            add_eh_table_entry (NOTE_BLOCK_NUMBER (insn));
#ifdef ASM_OUTPUT_EH_REGION_BEG
          ASM_OUTPUT_EH_REGION_BEG (file, NOTE_BLOCK_NUMBER (insn));
#endif
          break;
        }

      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END
          && ! exceptions_via_longjmp)
        {
          ASM_OUTPUT_INTERNAL_LABEL (file, "LEHE", NOTE_BLOCK_NUMBER (insn));
          if (flag_new_exceptions)
            add_eh_table_entry (NOTE_BLOCK_NUMBER (insn));
#ifdef ASM_OUTPUT_EH_REGION_END
          ASM_OUTPUT_EH_REGION_END (file, NOTE_BLOCK_NUMBER (insn));
#endif
          break;
        }

      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_PROLOGUE_END)
        {
#ifdef FUNCTION_END_PROLOGUE
          FUNCTION_END_PROLOGUE (file);
#endif
          profile_after_prologue (file);
          break;
        }

#ifdef FUNCTION_BEGIN_EPILOGUE
      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EPILOGUE_BEG)
        {
          FUNCTION_BEGIN_EPILOGUE (file);
          break;
        }
#endif

      if (write_symbols == NO_DEBUG)
        break;
      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_FUNCTION_BEG)
        {
#if defined(SDB_DEBUGGING_INFO) && defined(MIPS_DEBUGGING_INFO)
          /* MIPS stabs require the parameter descriptions to be after the
             function entry point rather than before.  */
          if (write_symbols == SDB_DEBUG)
            sdbout_begin_function (last_linenum);
          else
#endif
#ifdef DWARF_DEBUGGING_INFO
          /* This outputs a marker where the function body starts, so it
             must be after the prologue.  */
          if (write_symbols == DWARF_DEBUG)
            dwarfout_begin_function ();
#endif
          break;
        }
      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_DELETED)
        break;                  /* An insn that was "deleted" */
      if (app_on)
        {
          fputs (ASM_APP_OFF, file);
          app_on = 0;
        }
      if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
          && (debug_info_level == DINFO_LEVEL_NORMAL
              || debug_info_level == DINFO_LEVEL_VERBOSE
              || write_symbols == DWARF_DEBUG
              || write_symbols == DWARF2_DEBUG))
        {
          /* Beginning of a symbol-block.  Assign it a sequence number
             and push the number onto the stack PENDING_BLOCKS.  */

          if (block_depth == max_block_depth)
            {
              /* PENDING_BLOCKS is full; make it longer.  */
              max_block_depth *= 2;
              pending_blocks
                = (int *) xrealloc (pending_blocks,
                                    max_block_depth * sizeof (int));
            }
          pending_blocks[block_depth++] = next_block_index;

          high_block_linenum = last_linenum;

          /* Output debugging info about the symbol-block beginning.  */

#ifdef SDB_DEBUGGING_INFO
          if (write_symbols == SDB_DEBUG)
            sdbout_begin_block (file, last_linenum, next_block_index);
#endif
#ifdef XCOFF_DEBUGGING_INFO
          if (write_symbols == XCOFF_DEBUG)
            xcoffout_begin_block (file, last_linenum, next_block_index);
#endif
#ifdef DBX_DEBUGGING_INFO
          if (write_symbols == DBX_DEBUG)
            ASM_OUTPUT_INTERNAL_LABEL (file, "LBB", next_block_index);
#endif
#ifdef DWARF_DEBUGGING_INFO
          if (write_symbols == DWARF_DEBUG)
            dwarfout_begin_block (next_block_index);
#endif
#ifdef DWARF2_DEBUGGING_INFO
          if (write_symbols == DWARF2_DEBUG)
            dwarf2out_begin_block (next_block_index);
#endif

          next_block_index++;
        }
      else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END
               && (debug_info_level == DINFO_LEVEL_NORMAL
                   || debug_info_level == DINFO_LEVEL_VERBOSE
                   || write_symbols == DWARF_DEBUG
                   || write_symbols == DWARF2_DEBUG))
        {
          /* End of a symbol-block.  Pop its sequence number off
             PENDING_BLOCKS and output debugging info based on that.  */

          --block_depth;
          if (block_depth < 0)
            abort ();

#ifdef XCOFF_DEBUGGING_INFO
          if (write_symbols == XCOFF_DEBUG)
            xcoffout_end_block (file, high_block_linenum,
                                pending_blocks[block_depth]);
#endif
#ifdef DBX_DEBUGGING_INFO
          if (write_symbols == DBX_DEBUG)
            ASM_OUTPUT_INTERNAL_LABEL (file, "LBE",
                                       pending_blocks[block_depth]);
#endif
#ifdef SDB_DEBUGGING_INFO
          if (write_symbols == SDB_DEBUG)
            sdbout_end_block (file, high_block_linenum,
                              pending_blocks[block_depth]);
#endif
#ifdef DWARF_DEBUGGING_INFO
          if (write_symbols == DWARF_DEBUG)
            dwarfout_end_block (pending_blocks[block_depth]);
#endif
#ifdef DWARF2_DEBUGGING_INFO
          if (write_symbols == DWARF2_DEBUG)
            dwarf2out_end_block (pending_blocks[block_depth]);
#endif
        }
      else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_DELETED_LABEL
               && (debug_info_level == DINFO_LEVEL_NORMAL
                   || debug_info_level == DINFO_LEVEL_VERBOSE))
        {
#ifdef DWARF_DEBUGGING_INFO
          if (write_symbols == DWARF_DEBUG)
            dwarfout_label (insn);
#endif
#ifdef DWARF2_DEBUGGING_INFO
          if (write_symbols == DWARF2_DEBUG)
            dwarf2out_label (insn);
#endif
        }
      else if (NOTE_LINE_NUMBER (insn) > 0)
        /* This note is a line-number.  */
        {
          register rtx note;

#if 0 /* This is what we used to do.  */
          output_source_line (file, insn);
#endif
          int note_after = 0;

          /* If there is anything real after this note,
             output it.  If another line note follows, omit this one.  */
          for (note = NEXT_INSN (insn); note; note = NEXT_INSN (note))
            {
              if (GET_CODE (note) != NOTE && GET_CODE (note) != CODE_LABEL)
                break;
              /* These types of notes can be significant
                 so make sure the preceding line number stays.  */
              else if (GET_CODE (note) == NOTE
                       && (NOTE_LINE_NUMBER (note) == NOTE_INSN_BLOCK_BEG
                           || NOTE_LINE_NUMBER (note) == NOTE_INSN_BLOCK_END
                           || NOTE_LINE_NUMBER (note) == NOTE_INSN_FUNCTION_BEG))
                break;
              else if (GET_CODE (note) == NOTE && NOTE_LINE_NUMBER (note) > 0)
                {
                  /* Another line note follows; we can delete this note
                     if no intervening line numbers have notes elsewhere.  */
                  int num;
                  for (num = NOTE_LINE_NUMBER (insn) + 1;
                       num < NOTE_LINE_NUMBER (note);
                       num++)
                    if (line_note_exists[num])
                      break;

                  if (num >= NOTE_LINE_NUMBER (note))
                    note_after = 1;
                  break;
                }
            }

          /* Output this line note
             if it is the first or the last line note in a row.  */
          if (!note_after)
            output_source_line (file, insn);
        }
      break;

    case BARRIER:
#if defined (DWARF2_UNWIND_INFO) && !defined (ACCUMULATE_OUTGOING_ARGS)
        /* If we push arguments, we need to check all insns for stack
           adjustments.  */
        if (dwarf2out_do_frame ())
          dwarf2out_frame_debug (insn);
#endif
      break;

    case CODE_LABEL:
      /* The target port might emit labels in the output function for
         some insn, e.g. sh.c output_branchy_insn.  */
      if (CODE_LABEL_NUMBER (insn) <= max_labelno)
        {
          int align = LABEL_TO_ALIGNMENT (insn);
#ifdef ASM_OUTPUT_MAX_SKIP_ALIGN
          int max_skip = LABEL_TO_MAX_SKIP (insn);
#endif

          if (align && NEXT_INSN (insn))
#ifdef ASM_OUTPUT_MAX_SKIP_ALIGN
            ASM_OUTPUT_MAX_SKIP_ALIGN (file, align, max_skip);
#else
            ASM_OUTPUT_ALIGN (file, align);
#endif
        }
#ifdef HAVE_cc0
      CC_STATUS_INIT;
      /* If this label is reached from only one place, set the condition
         codes from the instruction just before the branch.  */

      /* Disabled because some insns set cc_status in the C output code
         and NOTICE_UPDATE_CC alone can set incorrect status.  */
      if (0 /* optimize && LABEL_NUSES (insn) == 1*/)
        {
          rtx jump = LABEL_REFS (insn);
          rtx barrier = prev_nonnote_insn (insn);
          rtx prev;
          /* If the LABEL_REFS field of this label has been set to point
             at a branch, the predecessor of the branch is a regular
             insn, and that branch is the only way to reach this label,
             set the condition codes based on the branch and its
             predecessor.  */
          if (barrier && GET_CODE (barrier) == BARRIER
              && jump && GET_CODE (jump) == JUMP_INSN
              && (prev = prev_nonnote_insn (jump))
              && GET_CODE (prev) == INSN)
            {
              NOTICE_UPDATE_CC (PATTERN (prev), prev);
              NOTICE_UPDATE_CC (PATTERN (jump), jump);
            }
        }
#endif
      if (prescan > 0)
        break;
      new_block = 1;

#ifdef FINAL_PRESCAN_LABEL
      FINAL_PRESCAN_INSN (insn, NULL_PTR, 0);
#endif

#ifdef SDB_DEBUGGING_INFO
      if (write_symbols == SDB_DEBUG && LABEL_NAME (insn))
        sdbout_label (insn);
#endif
#ifdef DWARF_DEBUGGING_INFO
      if (write_symbols == DWARF_DEBUG && LABEL_NAME (insn))
        dwarfout_label (insn);
#endif
#ifdef DWARF2_DEBUGGING_INFO
      if (write_symbols == DWARF2_DEBUG && LABEL_NAME (insn))
        dwarf2out_label (insn);
#endif
      if (app_on)
        {
          fputs (ASM_APP_OFF, file);
          app_on = 0;
        }
      if (NEXT_INSN (insn) != 0
          && GET_CODE (NEXT_INSN (insn)) == JUMP_INSN)
        {
          rtx nextbody = PATTERN (NEXT_INSN (insn));

          /* If this label is followed by a jump-table,
             make sure we put the label in the read-only section.  Also
             possibly write the label and jump table together.  */

          if (GET_CODE (nextbody) == ADDR_VEC
              || GET_CODE (nextbody) == ADDR_DIFF_VEC)
            {
#if defined(ASM_OUTPUT_ADDR_VEC) || defined(ASM_OUTPUT_ADDR_DIFF_VEC)
              /* In this case, the case vector is being moved by the
                 target, so don't output the label at all.  Leave that
                 to the back end macros.  */
#else
              if (! JUMP_TABLES_IN_TEXT_SECTION)
                {
                  readonly_data_section ();
#ifdef READONLY_DATA_SECTION
                  ASM_OUTPUT_ALIGN (file,
                                    exact_log2 (BIGGEST_ALIGNMENT
                                                / BITS_PER_UNIT));
#endif /* READONLY_DATA_SECTION */
                }
              else
                function_section (current_function_decl);

#ifdef ASM_OUTPUT_CASE_LABEL
              ASM_OUTPUT_CASE_LABEL (file, "L", CODE_LABEL_NUMBER (insn),
                                     NEXT_INSN (insn));
#else
              ASM_OUTPUT_INTERNAL_LABEL (file, "L", CODE_LABEL_NUMBER (insn));
#endif
#endif
              break;
            }
        }

      ASM_OUTPUT_INTERNAL_LABEL (file, "L", CODE_LABEL_NUMBER (insn));
      break;

    default:
      {
        register rtx body = PATTERN (insn);
        int insn_code_number;
        const char *template;
#ifdef HAVE_cc0
        rtx note;
#endif

        /* An INSN, JUMP_INSN or CALL_INSN.
           First check for special kinds that recog doesn't recognize.  */

        if (GET_CODE (body) == USE /* These are just declarations */
            || GET_CODE (body) == CLOBBER)
          break;

#ifdef HAVE_cc0
        /* If there is a REG_CC_SETTER note on this insn, it means that
           the setting of the condition code was done in the delay slot
           of the insn that branched here.  So recover the cc status
           from the insn that set it.  */

        note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
        if (note)
          {
            NOTICE_UPDATE_CC (PATTERN (XEXP (note, 0)), XEXP (note, 0));
            cc_prev_status = cc_status;
          }
#endif

        /* Detect insns that are really jump-tables
           and output them as such.  */

        if (GET_CODE (body) == ADDR_VEC || GET_CODE (body) == ADDR_DIFF_VEC)
          {
#if !(defined(ASM_OUTPUT_ADDR_VEC) || defined(ASM_OUTPUT_ADDR_DIFF_VEC))
            register int vlen, idx;
#endif

            if (prescan > 0)
              break;

            if (app_on)
              {
                fputs (ASM_APP_OFF, file);
                app_on = 0;
              }

#if defined(ASM_OUTPUT_ADDR_VEC) || defined(ASM_OUTPUT_ADDR_DIFF_VEC)
            if (GET_CODE (body) == ADDR_VEC)
              {
#ifdef ASM_OUTPUT_ADDR_VEC
                ASM_OUTPUT_ADDR_VEC (PREV_INSN (insn), body);
#else
                abort();
#endif
              }
            else
              {
#ifdef ASM_OUTPUT_ADDR_DIFF_VEC
                ASM_OUTPUT_ADDR_DIFF_VEC (PREV_INSN (insn), body);
#else
                abort();
#endif
              }
#else
            vlen = XVECLEN (body, GET_CODE (body) == ADDR_DIFF_VEC);
            for (idx = 0; idx < vlen; idx++)
              {
                if (GET_CODE (body) == ADDR_VEC)
                  {
#ifdef ASM_OUTPUT_ADDR_VEC_ELT
                    ASM_OUTPUT_ADDR_VEC_ELT
                      (file, CODE_LABEL_NUMBER (XEXP (XVECEXP (body, 0, idx), 0)));
#else
                    abort ();
#endif
                  }
                else
                  {
#ifdef ASM_OUTPUT_ADDR_DIFF_ELT
                    ASM_OUTPUT_ADDR_DIFF_ELT
                      (file,
                       body,
                       CODE_LABEL_NUMBER (XEXP (XVECEXP (body, 1, idx), 0)),
                       CODE_LABEL_NUMBER (XEXP (XEXP (body, 0), 0)));
#else
                    abort ();
#endif
                  }
              }
#ifdef ASM_OUTPUT_CASE_END
            ASM_OUTPUT_CASE_END (file,
                                 CODE_LABEL_NUMBER (PREV_INSN (insn)),
                                 insn);
#endif
#endif

            function_section (current_function_decl);

            break;
          }

        /* Do basic-block profiling when we reach a new block.
           Done here to avoid jump tables.  */
        if (profile_block_flag && new_block)
          add_bb (file);

        if (GET_CODE (body) == ASM_INPUT)
          {
            /* There's no telling what that did to the condition codes.  */
            CC_STATUS_INIT;
            if (prescan > 0)
              break;
            if (! app_on)
              {
                fputs (ASM_APP_ON, file);
                app_on = 1;
              }
            fprintf (asm_out_file, "\t%s\n", XSTR (body, 0));
            break;
          }

        /* Detect `asm' construct with operands.  */
        if (asm_noperands (body) >= 0)
          {
            unsigned int noperands = asm_noperands (body);
            rtx *ops = (rtx *) alloca (noperands * sizeof (rtx));
            char *string;

            /* There's no telling what that did to the condition codes.  */
            CC_STATUS_INIT;
            if (prescan > 0)
              break;

            if (! app_on)
              {
                fputs (ASM_APP_ON, file);
                app_on = 1;
              }

            /* Get out the operand values.  */
            string = decode_asm_operands (body, ops, NULL_PTR,
                                          NULL_PTR, NULL_PTR);
            /* Inhibit aborts on what would otherwise be compiler bugs.  */
            insn_noperands = noperands;
            this_is_asm_operands = insn;

            /* Output the insn using them.  */
            output_asm_insn (string, ops);
            this_is_asm_operands = 0;
            break;
          }

        if (prescan <= 0 && app_on)
          {
            fputs (ASM_APP_OFF, file);
            app_on = 0;
          }

        if (GET_CODE (body) == SEQUENCE)
          {
            /* A delayed-branch sequence */
            register int i;
            rtx next;

            if (prescan > 0)
              break;
            final_sequence = body;

            /* The first insn in this SEQUENCE might be a JUMP_INSN that will
               force the restoration of a comparison that was previously
               thought unnecessary.  If that happens, cancel this sequence
               and cause that insn to be restored.  */

            next = final_scan_insn (XVECEXP (body, 0, 0), file, 0, prescan, 1);
            if (next != XVECEXP (body, 0, 1))
              {
                final_sequence = 0;
                return next;
              }

            for (i = 1; i < XVECLEN (body, 0); i++)
              {
                rtx insn = XVECEXP (body, 0, i);
                rtx next = NEXT_INSN (insn);
                /* We loop in case any instruction in a delay slot gets
                   split.  */
                do
                  insn = final_scan_insn (insn, file, 0, prescan, 1);
                while (insn != next);
              }
#ifdef DBR_OUTPUT_SEQEND
            DBR_OUTPUT_SEQEND (file);
#endif
            final_sequence = 0;

            /* If the insn requiring the delay slot was a CALL_INSN, the
               insns in the delay slot are actually executed before the
               called function.  Hence we don't preserve any CC-setting
               actions in these insns and the CC must be marked as being
               clobbered by the function.  */
            if (GET_CODE (XVECEXP (body, 0, 0)) == CALL_INSN)
              {
                CC_STATUS_INIT;
              }

            /* Following a conditional branch sequence, we have a new basic
               block.  */
            if (profile_block_flag)
              {
                rtx insn = XVECEXP (body, 0, 0);
                rtx body = PATTERN (insn);

                if ((GET_CODE (insn) == JUMP_INSN && GET_CODE (body) == SET
                     && GET_CODE (SET_SRC (body)) != LABEL_REF)
                    || (GET_CODE (insn) == JUMP_INSN
                        && GET_CODE (body) == PARALLEL
                        && GET_CODE (XVECEXP (body, 0, 0)) == SET
                        && GET_CODE (SET_SRC (XVECEXP (body, 0, 0))) != LABEL_REF))
                  new_block = 1;
              }
            break;
          }

        /* We have a real machine instruction as rtl.  */

        body = PATTERN (insn);

#ifdef HAVE_cc0
        set = single_set(insn);

        /* Check for redundant test and compare instructions
           (when the condition codes are already set up as desired).
           This is done only when optimizing; if not optimizing,
           it should be possible for the user to alter a variable
           with the debugger in between statements
           and the next statement should reexamine the variable
           to compute the condition codes.  */

        if (optimize)
          {
#if 0
            rtx set = single_set(insn);
#endif

            if (set
                && GET_CODE (SET_DEST (set)) == CC0
                && insn != last_ignored_compare)
              {
                if (GET_CODE (SET_SRC (set)) == SUBREG)
                  SET_SRC (set) = alter_subreg (SET_SRC (set));
                else if (GET_CODE (SET_SRC (set)) == COMPARE)
                  {
                    if (GET_CODE (XEXP (SET_SRC (set), 0)) == SUBREG)
                      XEXP (SET_SRC (set), 0)
                        = alter_subreg (XEXP (SET_SRC (set), 0));
                    if (GET_CODE (XEXP (SET_SRC (set), 1)) == SUBREG)
                      XEXP (SET_SRC (set), 1)
                        = alter_subreg (XEXP (SET_SRC (set), 1));
                  }
                if ((cc_status.value1 != 0
                     && rtx_equal_p (SET_SRC (set), cc_status.value1))
                    || (cc_status.value2 != 0
                        && rtx_equal_p (SET_SRC (set), cc_status.value2)))
                  {
                    /* Don't delete insn if it has an addressing side-effect.  */
                    if (! FIND_REG_INC_NOTE (insn, 0)
                        /* or if anything in it is volatile.  */
                        && ! volatile_refs_p (PATTERN (insn)))
                      {
                        /* We don't really delete the insn; just ignore it.  */
                        last_ignored_compare = insn;
                        break;
                      }
                  }
              }
          }
#endif

        /* Following a conditional branch, we have a new basic block.
           But if we are inside a sequence, the new block starts after the
           last insn of the sequence.  */
        if (profile_block_flag && final_sequence == 0
            && ((GET_CODE (insn) == JUMP_INSN && GET_CODE (body) == SET
                 && GET_CODE (SET_SRC (body)) != LABEL_REF)
                || (GET_CODE (insn) == JUMP_INSN && GET_CODE (body) == PARALLEL
                    && GET_CODE (XVECEXP (body, 0, 0)) == SET
                    && GET_CODE (SET_SRC (XVECEXP (body, 0, 0))) != LABEL_REF)))
          new_block = 1;

#ifndef STACK_REGS
        /* Don't bother outputting obvious no-ops, even without -O.
           This optimization is fast and doesn't interfere with debugging.
           Don't do this if the insn is in a delay slot, since this
           will cause an improper number of delay insns to be written.  */
        if (final_sequence == 0
            && prescan >= 0
            && GET_CODE (insn) == INSN && GET_CODE (body) == SET
            && GET_CODE (SET_SRC (body)) == REG
            && GET_CODE (SET_DEST (body)) == REG
            && REGNO (SET_SRC (body)) == REGNO (SET_DEST (body)))
          break;
#endif

#ifdef HAVE_cc0
        /* If this is a conditional branch, maybe modify it
           if the cc's are in a nonstandard state
           so that it accomplishes the same thing that it would
           do straightforwardly if the cc's were set up normally.  */

        if (cc_status.flags != 0
            && GET_CODE (insn) == JUMP_INSN
            && GET_CODE (body) == SET
            && SET_DEST (body) == pc_rtx
            && GET_CODE (SET_SRC (body)) == IF_THEN_ELSE
            && GET_RTX_CLASS (GET_CODE (XEXP (SET_SRC (body), 0))) == '<'
            && XEXP (XEXP (SET_SRC (body), 0), 0) == cc0_rtx
            /* This is done during prescan; it is not done again
               in final scan when prescan has been done.  */
            && prescan >= 0)
          {
            /* This function may alter the contents of its argument
               and clear some of the cc_status.flags bits.
               It may also return 1 meaning condition now always true
               or -1 meaning condition now always false
               or 2 meaning condition nontrivial but altered.  */
            register int result = alter_cond (XEXP (SET_SRC (body), 0));
            /* If condition now has fixed value, replace the IF_THEN_ELSE
               with its then-operand or its else-operand.  */
            if (result == 1)
              SET_SRC (body) = XEXP (SET_SRC (body), 1);
            if (result == -1)
              SET_SRC (body) = XEXP (SET_SRC (body), 2);

            /* The jump is now either unconditional or a no-op.
               If it has become a no-op, don't try to output it.
               (It would not be recognized.)  */
            if (SET_SRC (body) == pc_rtx)
              {
                PUT_CODE (insn, NOTE);
                NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
                NOTE_SOURCE_FILE (insn) = 0;
                break;
              }
            else if (GET_CODE (SET_SRC (body)) == RETURN)
              /* Replace (set (pc) (return)) with (return).  */
              PATTERN (insn) = body = SET_SRC (body);

            /* Rerecognize the instruction if it has changed.  */
            if (result != 0)
              INSN_CODE (insn) = -1;
          }

        /* Make same adjustments to instructions that examine the
           condition codes without jumping and instructions that
           handle conditional moves (if this machine has either one).  */

        if (cc_status.flags != 0
            && set != 0)
          {
            rtx cond_rtx, then_rtx, else_rtx;
            
            if (GET_CODE (insn) != JUMP_INSN
                && GET_CODE (SET_SRC (set)) == IF_THEN_ELSE)
              {
                cond_rtx = XEXP (SET_SRC (set), 0);
                then_rtx = XEXP (SET_SRC (set), 1);
                else_rtx = XEXP (SET_SRC (set), 2);
              }
            else
              {
                cond_rtx = SET_SRC (set);
                then_rtx = const_true_rtx;
                else_rtx = const0_rtx;
              }
            
            switch (GET_CODE (cond_rtx))
              {
              case GTU:
              case GT:
              case LTU:
              case LT:
              case GEU:
              case GE:
              case LEU:
              case LE:
              case EQ:
              case NE:
                {
                  register int result;
                  if (XEXP (cond_rtx, 0) != cc0_rtx)
                    break;
                  result = alter_cond (cond_rtx);
                  if (result == 1)
                    validate_change (insn, &SET_SRC (set), then_rtx, 0);
                  else if (result == -1)
                    validate_change (insn, &SET_SRC (set), else_rtx, 0);
                  else if (result == 2)
                    INSN_CODE (insn) = -1;
                  if (SET_DEST (set) == SET_SRC (set))
                    {
                      PUT_CODE (insn, NOTE);
                      NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED;
                      NOTE_SOURCE_FILE (insn) = 0;
                    }
                }
                break;

              default:
                break;
              }
          }

#endif

        /* Do machine-specific peephole optimizations if desired.  */

        if (optimize && !flag_no_peephole && !nopeepholes)
          {
            rtx next = peephole (insn);
            /* When peepholing, if there were notes within the peephole,
               emit them before the peephole.  */
            if (next != 0 && next != NEXT_INSN (insn))
              {
                rtx prev = PREV_INSN (insn);
                rtx note;

                for (note = NEXT_INSN (insn); note != next;
                     note = NEXT_INSN (note))
                  final_scan_insn (note, file, optimize, prescan, nopeepholes);

                /* In case this is prescan, put the notes
                   in proper position for later rescan.  */
                note = NEXT_INSN (insn);
                PREV_INSN (note) = prev;
                NEXT_INSN (prev) = note;
                NEXT_INSN (PREV_INSN (next)) = insn;
                PREV_INSN (insn) = PREV_INSN (next);
                NEXT_INSN (insn) = next;
                PREV_INSN (next) = insn;
              }

            /* PEEPHOLE might have changed this.  */
            body = PATTERN (insn);
          }

        /* Try to recognize the instruction.
           If successful, verify that the operands satisfy the
           constraints for the instruction.  Crash if they don't,
           since `reload' should have changed them so that they do.  */

        insn_code_number = recog_memoized (insn);
        extract_insn (insn);
        cleanup_subreg_operands (insn);

#ifdef REGISTER_CONSTRAINTS
        if (! constrain_operands (1))
          fatal_insn_not_found (insn);
#endif

        /* Some target machines need to prescan each insn before
           it is output.  */

#ifdef FINAL_PRESCAN_INSN
        FINAL_PRESCAN_INSN (insn, recog_operand, recog_n_operands);
#endif

#ifdef HAVE_cc0
        cc_prev_status = cc_status;

        /* Update `cc_status' for this instruction.
           The instruction's output routine may change it further.
           If the output routine for a jump insn needs to depend
           on the cc status, it should look at cc_prev_status.  */

        NOTICE_UPDATE_CC (body, insn);
#endif

        debug_insn = insn;

#if defined (DWARF2_UNWIND_INFO) && !defined (ACCUMULATE_OUTGOING_ARGS)
        /* If we push arguments, we want to know where the calls are.  */
        if (GET_CODE (insn) == CALL_INSN && dwarf2out_do_frame ())
          dwarf2out_frame_debug (insn);
#endif

        /* If the proper template needs to be chosen by some C code,
           run that code and get the real template.  */

        template = insn_template[insn_code_number];
        if (template == 0)
          {
            template = (*insn_outfun[insn_code_number]) (recog_operand, insn);

            /* If the C code returns 0, it means that it is a jump insn
               which follows a deleted test insn, and that test insn
               needs to be reinserted.  */
            if (template == 0)
              {
                if (prev_nonnote_insn (insn) != last_ignored_compare)
                  abort ();
                new_block = 0;
                return prev_nonnote_insn (insn);
              }
          }

        /* If the template is the string "#", it means that this insn must
           be split.  */
        if (template[0] == '#' && template[1] == '\0')
          {
            rtx new = try_split (body, insn, 0);

            /* If we didn't split the insn, go away.  */
            if (new == insn && PATTERN (new) == body)
              fatal_insn ("Could not split insn", insn);
              
#ifdef HAVE_ATTR_length
            /* This instruction should have been split in shorten_branches,
               to ensure that we would have valid length info for the
               splitees.  */
            abort ();
#endif

            new_block = 0;
            return new;
          }
        
        if (prescan > 0)
          break;

        /* Output assembler code from the template.  */

        output_asm_insn (template, recog_operand);

#if defined (DWARF2_UNWIND_INFO)
#if !defined (ACCUMULATE_OUTGOING_ARGS)
        /* If we push arguments, we need to check all insns for stack
           adjustments.  */
        if (GET_CODE (insn) == INSN && dwarf2out_do_frame ())
          dwarf2out_frame_debug (insn);
#else
#if defined (HAVE_prologue)
        /* If this insn is part of the prologue, emit DWARF v2
           call frame info.  */
        if (RTX_FRAME_RELATED_P (insn) && dwarf2out_do_frame ())
          dwarf2out_frame_debug (insn);
#endif
#endif
#endif

#if 0
        /* It's not at all clear why we did this and doing so interferes
           with tests we'd like to do to use REG_WAS_0 notes, so let's try
           with this out.  */

        /* Mark this insn as having been output.  */
        INSN_DELETED_P (insn) = 1;
#endif

        debug_insn = 0;
      }
    }
  return NEXT_INSN (insn);
}
\f
/* Output debugging info to the assembler file FILE
   based on the NOTE-insn INSN, assumed to be a line number.  */

static void
output_source_line (file, insn)
     FILE *file;
     rtx insn;
{
  register char *filename = NOTE_SOURCE_FILE (insn);

  /* Remember filename for basic block profiling.
     Filenames are allocated on the permanent obstack
     or are passed in ARGV, so we don't have to save
     the string.  */

  if (profile_block_flag && last_filename != filename)
    bb_file_label_num = add_bb_string (filename, TRUE);

  last_filename = filename;
  last_linenum = NOTE_LINE_NUMBER (insn);
  high_block_linenum = MAX (last_linenum, high_block_linenum);
  high_function_linenum = MAX (last_linenum, high_function_linenum);

  if (write_symbols != NO_DEBUG)
    {
#ifdef SDB_DEBUGGING_INFO
      if (write_symbols == SDB_DEBUG
#if 0 /* People like having line numbers even in wrong file!  */
          /* COFF can't handle multiple source files--lose, lose.  */
          && !strcmp (filename, main_input_filename)
#endif
          /* COFF relative line numbers must be positive.  */
          && last_linenum > sdb_begin_function_line)
        {
#ifdef ASM_OUTPUT_SOURCE_LINE
          ASM_OUTPUT_SOURCE_LINE (file, last_linenum);
#else
          fprintf (file, "\t.ln\t%d\n",
                   ((sdb_begin_function_line > -1)
                    ? last_linenum - sdb_begin_function_line : 1));
#endif
        }
#endif

#if defined (DBX_DEBUGGING_INFO)
      if (write_symbols == DBX_DEBUG)
        dbxout_source_line (file, filename, NOTE_LINE_NUMBER (insn));
#endif

#if defined (XCOFF_DEBUGGING_INFO)
      if (write_symbols == XCOFF_DEBUG)
        xcoffout_source_line (file, filename, insn);
#endif

#ifdef DWARF_DEBUGGING_INFO
      if (write_symbols == DWARF_DEBUG)
        dwarfout_line (filename, NOTE_LINE_NUMBER (insn));
#endif

#ifdef DWARF2_DEBUGGING_INFO
      if (write_symbols == DWARF2_DEBUG)
        dwarf2out_line (filename, NOTE_LINE_NUMBER (insn));
#endif
    }
}
\f

/* For each operand in INSN, simplify (subreg (reg)) so that it refers
   directly to the desired hard register.  */
void
cleanup_subreg_operands (insn)
     rtx insn;
{
  int i;

  extract_insn (insn);
  for (i = 0; i < recog_n_operands; i++)
    {
      if (GET_CODE (recog_operand[i]) == SUBREG)
        recog_operand[i] = alter_subreg (recog_operand[i]);
      else if (GET_CODE (recog_operand[i]) == PLUS
               || GET_CODE (recog_operand[i]) == MULT
               || GET_CODE (recog_operand[i]) == MEM)
       recog_operand[i] = walk_alter_subreg (recog_operand[i]);
    }

  for (i = 0; i < recog_n_dups; i++)
    {
      if (GET_CODE (*recog_dup_loc[i]) == SUBREG)
        *recog_dup_loc[i] = alter_subreg (*recog_dup_loc[i]);
      else if (GET_CODE (*recog_dup_loc[i]) == PLUS
               || GET_CODE (*recog_dup_loc[i]) == MULT
               || GET_CODE (*recog_dup_loc[i]) == MEM)
        *recog_dup_loc[i] = walk_alter_subreg (*recog_dup_loc[i]);
    }
}

/* If X is a SUBREG, replace it with a REG or a MEM,
   based on the thing it is a subreg of.  */

rtx
alter_subreg (x)
     register rtx x;
{
  register rtx y = SUBREG_REG (x);

  if (GET_CODE (y) == SUBREG)
    y = alter_subreg (y);

  /* If reload is operating, we may be replacing inside this SUBREG.
     Check for that and make a new one if so.  */
  if (reload_in_progress && find_replacement (&SUBREG_REG (x)) != 0)
    x = copy_rtx (x);

  if (GET_CODE (y) == REG)
    {
      /* If the word size is larger than the size of this register,
         adjust the register number to compensate.  */
      /* ??? Note that this just catches stragglers created by/for
         integrate.  It would be better if we either caught these
         earlier, or kept _all_ subregs until now and eliminate
         gen_lowpart and friends.  */

      PUT_CODE (x, REG);
#ifdef ALTER_HARD_SUBREG
      REGNO (x) = ALTER_HARD_SUBREG(GET_MODE (x), SUBREG_WORD (x),
                                    GET_MODE (y), REGNO (y));
#else
      REGNO (x) = REGNO (y) + SUBREG_WORD (x);
#endif
      /* This field has a different meaning for REGs and SUBREGs.  Make sure
         to clear it!  */
      x->used = 0;
    }
  else if (GET_CODE (y) == MEM)
    {
      register int offset = SUBREG_WORD (x) * UNITS_PER_WORD;
      if (BYTES_BIG_ENDIAN)
        offset -= (MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (x)))
                   - MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (y))));
      PUT_CODE (x, MEM);
      MEM_COPY_ATTRIBUTES (x, y);
      MEM_ALIAS_SET (x) = MEM_ALIAS_SET (y);
      XEXP (x, 0) = plus_constant_for_output (XEXP (y, 0), offset);
    }

  return x;
}

/* Do alter_subreg on all the SUBREGs contained in X.  */

static rtx
walk_alter_subreg (x)
     rtx x;
{
  switch (GET_CODE (x))
    {
    case PLUS:
    case MULT:
      XEXP (x, 0) = walk_alter_subreg (XEXP (x, 0));
      XEXP (x, 1) = walk_alter_subreg (XEXP (x, 1));
      break;

    case MEM:
      XEXP (x, 0) = walk_alter_subreg (XEXP (x, 0));
      break;

    case SUBREG:
      return alter_subreg (x);
      
    default:
      break;
    }

  return x;
}
\f
#ifdef HAVE_cc0

/* Given BODY, the body of a jump instruction, alter the jump condition
   as required by the bits that are set in cc_status.flags.
   Not all of the bits there can be handled at this level in all cases.

   The value is normally 0.
   1 means that the condition has become always true.
   -1 means that the condition has become always false.
   2 means that COND has been altered.  */

static int
alter_cond (cond)
     register rtx cond;
{
  int value = 0;

  if (cc_status.flags & CC_REVERSED)
    {
      value = 2;
      PUT_CODE (cond, swap_condition (GET_CODE (cond)));
    }

  if (cc_status.flags & CC_INVERTED)
    {
      value = 2;
      PUT_CODE (cond, reverse_condition (GET_CODE (cond)));
    }

  if (cc_status.flags & CC_NOT_POSITIVE)
    switch (GET_CODE (cond))
      {
      case LE:
      case LEU:
      case GEU:
        /* Jump becomes unconditional.  */
        return 1;

      case GT:
      case GTU:
      case LTU:
        /* Jump becomes no-op.  */
        return -1;

      case GE:
        PUT_CODE (cond, EQ);
        value = 2;
        break;

      case LT:
        PUT_CODE (cond, NE);
        value = 2;
        break;
        
      default:
        break;
      }

  if (cc_status.flags & CC_NOT_NEGATIVE)
    switch (GET_CODE (cond))
      {
      case GE:
      case GEU:
        /* Jump becomes unconditional.  */
        return 1;

      case LT:
      case LTU:
        /* Jump becomes no-op.  */
        return -1;

      case LE:
      case LEU:
        PUT_CODE (cond, EQ);
        value = 2;
        break;

      case GT:
      case GTU:
        PUT_CODE (cond, NE);
        value = 2;
        break;
        
      default:
        break;
      }

  if (cc_status.flags & CC_NO_OVERFLOW)
    switch (GET_CODE (cond))
      {
      case GEU:
        /* Jump becomes unconditional.  */
        return 1;

      case LEU:
        PUT_CODE (cond, EQ);
        value = 2;
        break;

      case GTU:
        PUT_CODE (cond, NE);
        value = 2;
        break;

      case LTU:
        /* Jump becomes no-op.  */
        return -1;
        
      default:
        break;
      }

  if (cc_status.flags & (CC_Z_IN_NOT_N | CC_Z_IN_N))
    switch (GET_CODE (cond))
      {
      default:
        abort ();

      case NE:
        PUT_CODE (cond, cc_status.flags & CC_Z_IN_N ? GE : LT);
        value = 2;
        break;

      case EQ:
        PUT_CODE (cond, cc_status.flags & CC_Z_IN_N ? LT : GE);
        value = 2;
        break;
      }

  if (cc_status.flags & CC_NOT_SIGNED)
    /* The flags are valid if signed condition operators are converted
       to unsigned.  */
    switch (GET_CODE (cond))
      {
      case LE:
        PUT_CODE (cond, LEU);
        value = 2;
        break;

      case LT:
        PUT_CODE (cond, LTU);
        value = 2;
        break;

      case GT:
        PUT_CODE (cond, GTU);
        value = 2;
        break;

      case GE:
        PUT_CODE (cond, GEU);
        value = 2;
        break;

      default:
        break;
      }

  return value;
}
#endif
\f
/* Report inconsistency between the assembler template and the operands.
   In an `asm', it's the user's fault; otherwise, the compiler's fault.  */

void
output_operand_lossage (msgid)
     const char *msgid;
{
  if (this_is_asm_operands)
    error_for_asm (this_is_asm_operands, "invalid `asm': %s", _(msgid));
  else
    fatal ("Internal compiler error, output_operand_lossage `%s'", _(msgid));
}
\f
/* Output of assembler code from a template, and its subroutines.  */

/* Output text from TEMPLATE to the assembler output file,
   obeying %-directions to substitute operands taken from
   the vector OPERANDS.

   %N (for N a digit) means print operand N in usual manner.
   %lN means require operand N to be a CODE_LABEL or LABEL_REF
      and print the label name with no punctuation.
   %cN means require operand N to be a constant
      and print the constant expression with no punctuation.
   %aN means expect operand N to be a memory address
      (not a memory reference!) and print a reference
      to that address.
   %nN means expect operand N to be a constant
      and print a constant expression for minus the value
      of the operand, with no other punctuation.  */

static void
output_asm_name ()
{
  if (flag_print_asm_name)
    {
      /* Annotate the assembly with a comment describing the pattern and
         alternative used.  */
      if (debug_insn)
        {
          register int num = INSN_CODE (debug_insn);
          fprintf (asm_out_file, "\t%s %d\t%s", 
                   ASM_COMMENT_START, INSN_UID (debug_insn), insn_name[num]);
          if (insn_n_alternatives[num] > 1)
            fprintf (asm_out_file, "/%d", which_alternative + 1);
#ifdef HAVE_ATTR_length
          fprintf (asm_out_file, "\t[length = %d]", get_attr_length (debug_insn));
#endif
          /* Clear this so only the first assembler insn
             of any rtl insn will get the special comment for -dp.  */
          debug_insn = 0;
        }
    }
}

void
output_asm_insn (template, operands)
     const char *template;
     rtx *operands;
{
  register const char *p;
  register int c;

  /* An insn may return a null string template
     in a case where no assembler code is needed.  */
  if (*template == 0)
    return;

  p = template;
  putc ('\t', asm_out_file);

#ifdef ASM_OUTPUT_OPCODE
  ASM_OUTPUT_OPCODE (asm_out_file, p);
#endif

  while ((c = *p++))
    switch (c)
      {
      case '\n':
        output_asm_name ();
        putc (c, asm_out_file);
#ifdef ASM_OUTPUT_OPCODE
        while ((c = *p) == '\t')
          {
            putc (c, asm_out_file);
            p++;
          }
        ASM_OUTPUT_OPCODE (asm_out_file, p);
#endif
        break;

#ifdef ASSEMBLER_DIALECT
      case '{':
        {
          register int i;
          
          /* If we want the first dialect, do nothing.  Otherwise, skip
             DIALECT_NUMBER of strings ending with '|'.  */
          for (i = 0; i < dialect_number; i++)
            {
              while (*p && *p++ != '|')
                ;

              if (*p == '|')
                p++;
            }
        }
        break;

      case '|':
        /* Skip to close brace.  */
        while (*p && *p++ != '}')
          ;
        break;

      case '}':
        break;
#endif

      case '%':
        /* %% outputs a single %.  */
        if (*p == '%')
          {
            p++;
            putc (c, asm_out_file);
          }
        /* %= outputs a number which is unique to each insn in the entire
           compilation.  This is useful for making local labels that are
           referred to more than once in a given insn.  */
        else if (*p == '=')
          {
            p++;
            fprintf (asm_out_file, "%d", insn_counter);
          }
        /* % followed by a letter and some digits
           outputs an operand in a special way depending on the letter.
           Letters `acln' are implemented directly.
           Other letters are passed to `output_operand' so that
           the PRINT_OPERAND macro can define them.  */
        else if ((*p >= 'a' && *p <= 'z')
                 || (*p >= 'A' && *p <= 'Z'))
          {
            int letter = *p++;
            c = atoi (p);

            if (! (*p >= '0' && *p <= '9'))
              output_operand_lossage ("operand number missing after %-letter");
            else if (this_is_asm_operands && (c < 0 || (unsigned int) c >= insn_noperands))
              output_operand_lossage ("operand number out of range");
            else if (letter == 'l')
              output_asm_label (operands[c]);
            else if (letter == 'a')
              output_address (operands[c]);
            else if (letter == 'c')
              {
                if (CONSTANT_ADDRESS_P (operands[c]))
                  output_addr_const (asm_out_file, operands[c]);
                else
                  output_operand (operands[c], 'c');
              }
            else if (letter == 'n')
              {
                if (GET_CODE (operands[c]) == CONST_INT)
                  fprintf (asm_out_file, HOST_WIDE_INT_PRINT_DEC,
                           - INTVAL (operands[c]));
                else
                  {
                    putc ('-', asm_out_file);
                    output_addr_const (asm_out_file, operands[c]);
                  }
              }
            else
              output_operand (operands[c], letter);
            
            while ((c = *p) >= '0' && c <= '9') p++;
          }
        /* % followed by a digit outputs an operand the default way.  */
        else if (*p >= '0' && *p <= '9')
          {
            c = atoi (p);
            if (this_is_asm_operands && (c < 0 || (unsigned int) c >= insn_noperands))
              output_operand_lossage ("operand number out of range");
            else
              output_operand (operands[c], 0);
            while ((c = *p) >= '0' && c <= '9') p++;
          }
        /* % followed by punctuation: output something for that
           punctuation character alone, with no operand.
           The PRINT_OPERAND macro decides what is actually done.  */
#ifdef PRINT_OPERAND_PUNCT_VALID_P
        else if (PRINT_OPERAND_PUNCT_VALID_P ((unsigned char)*p))
          output_operand (NULL_RTX, *p++);
#endif
        else
          output_operand_lossage ("invalid %%-code");
        break;

      default:
        putc (c, asm_out_file);
      }

  output_asm_name ();

  putc ('\n', asm_out_file);
}
\f
/* Output a LABEL_REF, or a bare CODE_LABEL, as an assembler symbol.  */

void
output_asm_label (x)
     rtx x;
{
  char buf[256];

  if (GET_CODE (x) == LABEL_REF)
    ASM_GENERATE_INTERNAL_LABEL (buf, "L", CODE_LABEL_NUMBER (XEXP (x, 0)));
  else if (GET_CODE (x) == CODE_LABEL)
    ASM_GENERATE_INTERNAL_LABEL (buf, "L", CODE_LABEL_NUMBER (x));
  else
    output_operand_lossage ("`%l' operand isn't a label");

  assemble_name (asm_out_file, buf);
}

/* Print operand X using machine-dependent assembler syntax.
   The macro PRINT_OPERAND is defined just to control this function.
   CODE is a non-digit that preceded the operand-number in the % spec,
   such as 'z' if the spec was `%z3'.  CODE is 0 if there was no char
   between the % and the digits.
   When CODE is a non-letter, X is 0.

   The meanings of the letters are machine-dependent and controlled
   by PRINT_OPERAND.  */

static void
output_operand (x, code)
     rtx x;
     int code;
{
  if (x && GET_CODE (x) == SUBREG)
    x = alter_subreg (x);

  /* If X is a pseudo-register, abort now rather than writing trash to the
     assembler file.  */

  if (x && GET_CODE (x) == REG && REGNO (x) >= FIRST_PSEUDO_REGISTER)
    abort ();

  PRINT_OPERAND (asm_out_file, x, code);
}

/* Print a memory reference operand for address X
   using machine-dependent assembler syntax.
   The macro PRINT_OPERAND_ADDRESS exists just to control this function.  */

void
output_address (x)
     rtx x;
{
  walk_alter_subreg (x);
  PRINT_OPERAND_ADDRESS (asm_out_file, x);
}
\f
/* Print an integer constant expression in assembler syntax.
   Addition and subtraction are the only arithmetic
   that may appear in these expressions.  */

void
output_addr_const (file, x)
     FILE *file;
     rtx x;
{
  char buf[256];

 restart:
  switch (GET_CODE (x))
    {
    case PC:
      if (flag_pic)
        putc ('.', file);
      else
        abort ();
      break;

    case SYMBOL_REF:
      assemble_name (file, XSTR (x, 0));
      break;

    case LABEL_REF:
      ASM_GENERATE_INTERNAL_LABEL (buf, "L", CODE_LABEL_NUMBER (XEXP (x, 0)));
      assemble_name (file, buf);
      break;

    case CODE_LABEL:
      ASM_GENERATE_INTERNAL_LABEL (buf, "L", CODE_LABEL_NUMBER (x));
      assemble_name (file, buf);
      break;

    case CONST_INT:
      fprintf (file, HOST_WIDE_INT_PRINT_DEC, INTVAL (x));
      break;

    case CONST:
      /* This used to output parentheses around the expression,
         but that does not work on the 386 (either ATT or BSD assembler).  */
      output_addr_const (file, XEXP (x, 0));
      break;

    case CONST_DOUBLE:
      if (GET_MODE (x) == VOIDmode)
        {
          /* We can use %d if the number is one word and positive.  */
          if (CONST_DOUBLE_HIGH (x))
            fprintf (file, HOST_WIDE_INT_PRINT_DOUBLE_HEX,
                     CONST_DOUBLE_HIGH (x), CONST_DOUBLE_LOW (x));
          else if  (CONST_DOUBLE_LOW (x) < 0)
            fprintf (file, HOST_WIDE_INT_PRINT_HEX, CONST_DOUBLE_LOW (x));
          else
            fprintf (file, HOST_WIDE_INT_PRINT_DEC, CONST_DOUBLE_LOW (x));
        }
      else
        /* We can't handle floating point constants;
           PRINT_OPERAND must handle them.  */
        output_operand_lossage ("floating constant misused");
      break;

    case PLUS:
      /* Some assemblers need integer constants to appear last (eg masm).  */
      if (GET_CODE (XEXP (x, 0)) == CONST_INT)
        {
          output_addr_const (file, XEXP (x, 1));
          if (INTVAL (XEXP (x, 0)) >= 0)
            fprintf (file, "+");
          output_addr_const (file, XEXP (x, 0));
        }
      else
        {
          output_addr_const (file, XEXP (x, 0));
          if (INTVAL (XEXP (x, 1)) >= 0)
            fprintf (file, "+");
          output_addr_const (file, XEXP (x, 1));
        }
      break;

    case MINUS:
      /* Avoid outputting things like x-x or x+5-x,
         since some assemblers can't handle that.  */
      x = simplify_subtraction (x);
      if (GET_CODE (x) != MINUS)
        goto restart;

      output_addr_const (file, XEXP (x, 0));
      fprintf (file, "-");
      if (GET_CODE (XEXP (x, 1)) == CONST_INT
          && INTVAL (XEXP (x, 1)) < 0)
        {
          fprintf (file, ASM_OPEN_PAREN);
          output_addr_const (file, XEXP (x, 1));
          fprintf (file, ASM_CLOSE_PAREN);
        }
      else
        output_addr_const (file, XEXP (x, 1));
      break;

    case ZERO_EXTEND:
    case SIGN_EXTEND:
      output_addr_const (file, XEXP (x, 0));
      break;

    default:
      output_operand_lossage ("invalid expression as operand");
    }
}
\f
/* A poor man's fprintf, with the added features of %I, %R, %L, and %U.
   %R prints the value of REGISTER_PREFIX.
   %L prints the value of LOCAL_LABEL_PREFIX.
   %U prints the value of USER_LABEL_PREFIX.
   %I prints the value of IMMEDIATE_PREFIX.
   %O runs ASM_OUTPUT_OPCODE to transform what follows in the string.
   Also supported are %d, %x, %s, %e, %f, %g and %%.

   We handle alternate assembler dialects here, just like output_asm_insn.  */

void
asm_fprintf VPROTO((FILE *file, const char *p, ...))
{
#ifndef ANSI_PROTOTYPES
  FILE *file;
  const char *p;
#endif
  va_list argptr;
  char buf[10];
  char *q, c;

  VA_START (argptr, p);

#ifndef ANSI_PROTOTYPES
  file = va_arg (argptr, FILE *);
  p = va_arg (argptr, const char *);
#endif

  buf[0] = '%';

  while ((c = *p++))
    switch (c)
      {
#ifdef ASSEMBLER_DIALECT
      case '{':
        {
          int i;

          /* If we want the first dialect, do nothing.  Otherwise, skip
             DIALECT_NUMBER of strings ending with '|'.  */
          for (i = 0; i < dialect_number; i++)
            {
              while (*p && *p++ != '|')
                ;

              if (*p == '|')
                p++;
          }
        }
        break;

      case '|':
        /* Skip to close brace.  */
        while (*p && *p++ != '}')
          ;
        break;

      case '}':
        break;
#endif

      case '%':
        c = *p++;
        q = &buf[1];
        while ((c >= '0' && c <= '9') || c == '.')
          {
            *q++ = c;
            c = *p++;
          }
        switch (c)
          {
          case '%':
            fprintf (file, "%%");
            break;

          case 'd':  case 'i':  case 'u':
          case 'x':  case 'p':  case 'X':
          case 'o':
            *q++ = c;
            *q = 0;
            fprintf (file, buf, va_arg (argptr, int));
            break;

          case 'w':
            /* This is a prefix to the 'd', 'i', 'u', 'x', 'p', and 'X' cases,
               but we do not check for those cases.  It means that the value
               is a HOST_WIDE_INT, which may be either `int' or `long'.  */

#if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_INT
#else
#if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_LONG
            *q++ = 'l';
#else
            *q++ = 'l';
            *q++ = 'l';
#endif
#endif

            *q++ = *p++;
            *q = 0;
            fprintf (file, buf, va_arg (argptr, HOST_WIDE_INT));
            break;

          case 'l':
            *q++ = c;
            *q++ = *p++;
            *q = 0;
            fprintf (file, buf, va_arg (argptr, long));
            break;

          case 'e':
          case 'f':
          case 'g':
            *q++ = c;
            *q = 0;
            fprintf (file, buf, va_arg (argptr, double));
            break;

          case 's':
            *q++ = c;
            *q = 0;
            fprintf (file, buf, va_arg (argptr, char *));
            break;

          case 'O':
#ifdef ASM_OUTPUT_OPCODE
            ASM_OUTPUT_OPCODE (asm_out_file, p);
#endif
            break;

          case 'R':
#ifdef REGISTER_PREFIX
            fprintf (file, "%s", REGISTER_PREFIX);
#endif
            break;

          case 'I':
#ifdef IMMEDIATE_PREFIX
            fprintf (file, "%s", IMMEDIATE_PREFIX);
#endif
            break;

          case 'L':
#ifdef LOCAL_LABEL_PREFIX
            fprintf (file, "%s", LOCAL_LABEL_PREFIX);
#endif
            break;

          case 'U':
            fputs (user_label_prefix, file);
            break;

          default:
            abort ();
          }
        break;

      default:
        fputc (c, file);
      }
}
\f
/* Split up a CONST_DOUBLE or integer constant rtx
   into two rtx's for single words,
   storing in *FIRST the word that comes first in memory in the target
   and in *SECOND the other.  */

void
split_double (value, first, second)
     rtx value;
     rtx *first, *second;
{
  if (GET_CODE (value) == CONST_INT)
    {
      if (HOST_BITS_PER_WIDE_INT >= (2 * BITS_PER_WORD))
        {
          /* In this case the CONST_INT holds both target words.
             Extract the bits from it into two word-sized pieces.
             Sign extend each half to HOST_WIDE_INT.  */
          rtx low, high;
          /* On machines where HOST_BITS_PER_WIDE_INT == BITS_PER_WORD
             the shift below will cause a compiler warning, even though
             this code won't be executed.  So put the shift amounts in
             variables to avoid the warning.  */
          int rshift = HOST_BITS_PER_WIDE_INT - BITS_PER_WORD;
          int lshift = HOST_BITS_PER_WIDE_INT - 2 * BITS_PER_WORD;

          low = GEN_INT ((INTVAL (value) << rshift) >> rshift);
          high = GEN_INT ((INTVAL (value) << lshift) >> rshift);
          if (WORDS_BIG_ENDIAN)
            {
              *first = high;
              *second = low;
            }
          else
            {
              *first = low;
              *second = high;
            }
        }
      else
        {
          /* The rule for using CONST_INT for a wider mode
             is that we regard the value as signed.
             So sign-extend it.  */
          rtx high = (INTVAL (value) < 0 ? constm1_rtx : const0_rtx);
          if (WORDS_BIG_ENDIAN)
            {
              *first = high;
              *second = value;
            }
          else
            {
              *first = value;
              *second = high;
            }
        }
    }
  else if (GET_CODE (value) != CONST_DOUBLE)
    {
      if (WORDS_BIG_ENDIAN)
        {
          *first = const0_rtx;
          *second = value;
        }
      else
        {
          *first = value;
          *second = const0_rtx;
        }
    }
  else if (GET_MODE (value) == VOIDmode
           /* This is the old way we did CONST_DOUBLE integers.  */
           || GET_MODE_CLASS (GET_MODE (value)) == MODE_INT)
    {
      /* In an integer, the words are defined as most and least significant.
         So order them by the target's convention.  */
      if (WORDS_BIG_ENDIAN)
        {
          *first = GEN_INT (CONST_DOUBLE_HIGH (value));
          *second = GEN_INT (CONST_DOUBLE_LOW (value));
        }
      else
        {
          *first = GEN_INT (CONST_DOUBLE_LOW (value));
          *second = GEN_INT (CONST_DOUBLE_HIGH (value));
        }
    }
  else
    {
#ifdef REAL_ARITHMETIC
      REAL_VALUE_TYPE r; long l[2];
      REAL_VALUE_FROM_CONST_DOUBLE (r, value);

      /* Note, this converts the REAL_VALUE_TYPE to the target's
         format, splits up the floating point double and outputs
         exactly 32 bits of it into each of l[0] and l[1] --
         not necessarily BITS_PER_WORD bits.  */
      REAL_VALUE_TO_TARGET_DOUBLE (r, l);

      /* If 32 bits is an entire word for the target, but not for the host,
         then sign-extend on the host so that the number will look the same
         way on the host that it would on the target.  See for instance
         simplify_unary_operation.  The #if is needed to avoid compiler
         warnings.  */

#if HOST_BITS_PER_LONG > 32
      if (BITS_PER_WORD < HOST_BITS_PER_LONG && BITS_PER_WORD == 32)
        {
          if (l[0] & ((long) 1 << 31))
            l[0] |= ((long) (-1) << 32);
          if (l[1] & ((long) 1 << 31))
            l[1] |= ((long) (-1) << 32);
        }
#endif

      *first = GEN_INT ((HOST_WIDE_INT) l[0]);
      *second = GEN_INT ((HOST_WIDE_INT) l[1]);
#else
      if ((HOST_FLOAT_FORMAT != TARGET_FLOAT_FORMAT
           || HOST_BITS_PER_WIDE_INT != BITS_PER_WORD)
          && ! flag_pretend_float)
      abort ();

      if (
#ifdef HOST_WORDS_BIG_ENDIAN
          WORDS_BIG_ENDIAN
#else
          ! WORDS_BIG_ENDIAN
#endif
          )
        {
          /* Host and target agree => no need to swap.  */
          *first = GEN_INT (CONST_DOUBLE_LOW (value));
          *second = GEN_INT (CONST_DOUBLE_HIGH (value));
        }
      else
        {
          *second = GEN_INT (CONST_DOUBLE_LOW (value));
          *first = GEN_INT (CONST_DOUBLE_HIGH (value));
        }
#endif /* no REAL_ARITHMETIC */
    }
}
\f
/* Return nonzero if this function has no function calls.  */

int
leaf_function_p ()
{
  rtx insn;

  if (profile_flag || profile_block_flag || profile_arc_flag)
    return 0;

  for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
    {
      if (GET_CODE (insn) == CALL_INSN)
        return 0;
      if (GET_CODE (insn) == INSN
          && GET_CODE (PATTERN (insn)) == SEQUENCE
          && GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == CALL_INSN)
        return 0;
    }
  for (insn = current_function_epilogue_delay_list; insn; insn = XEXP (insn, 1))
    {
      if (GET_CODE (XEXP (insn, 0)) == CALL_INSN)
        return 0;
      if (GET_CODE (XEXP (insn, 0)) == INSN
          && GET_CODE (PATTERN (XEXP (insn, 0))) == SEQUENCE
          && GET_CODE (XVECEXP (PATTERN (XEXP (insn, 0)), 0, 0)) == CALL_INSN)
        return 0;
    }

  return 1;
}

/* On some machines, a function with no call insns
   can run faster if it doesn't create its own register window.
   When output, the leaf function should use only the "output"
   registers.  Ordinarily, the function would be compiled to use
   the "input" registers to find its arguments; it is a candidate
   for leaf treatment if it uses only the "input" registers.
   Leaf function treatment means renumbering so the function
   uses the "output" registers instead.  */

#ifdef LEAF_REGISTERS

static char permitted_reg_in_leaf_functions[] = LEAF_REGISTERS;

/* Return 1 if this function uses only the registers that can be
   safely renumbered.  */

int
only_leaf_regs_used ()
{
  int i;

  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
    if ((regs_ever_live[i] || global_regs[i])
        && ! permitted_reg_in_leaf_functions[i])
      return 0;

  if (current_function_uses_pic_offset_table
      && pic_offset_table_rtx != 0
      && GET_CODE (pic_offset_table_rtx) == REG
      && ! permitted_reg_in_leaf_functions[REGNO (pic_offset_table_rtx)])
    return 0;

  return 1;
}

/* Scan all instructions and renumber all registers into those
   available in leaf functions.  */

static void
leaf_renumber_regs (first)
     rtx first;
{
  rtx insn;

  /* Renumber only the actual patterns.
     The reg-notes can contain frame pointer refs,
     and renumbering them could crash, and should not be needed.  */
  for (insn = first; insn; insn = NEXT_INSN (insn))
    if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
      leaf_renumber_regs_insn (PATTERN (insn));
  for (insn = current_function_epilogue_delay_list; insn; insn = XEXP (insn, 1))
    if (GET_RTX_CLASS (GET_CODE (XEXP (insn, 0))) == 'i')
      leaf_renumber_regs_insn (PATTERN (XEXP (insn, 0)));
}

/* Scan IN_RTX and its subexpressions, and renumber all regs into those
   available in leaf functions.  */

void
leaf_renumber_regs_insn (in_rtx)
     register rtx in_rtx;
{
  register int i, j;
  register char *format_ptr;

  if (in_rtx == 0)
    return;

  /* Renumber all input-registers into output-registers.
     renumbered_regs would be 1 for an output-register;
     they  */

  if (GET_CODE (in_rtx) == REG)
    {
      int newreg;

      /* Don't renumber the same reg twice.  */
      if (in_rtx->used)
        return;

      newreg = REGNO (in_rtx);
      /* Don't try to renumber pseudo regs.  It is possible for a pseudo reg
         to reach here as part of a REG_NOTE.  */
      if (newreg >= FIRST_PSEUDO_REGISTER)
        {
          in_rtx->used = 1;
          return;
        }
      newreg = LEAF_REG_REMAP (newreg);
      if (newreg < 0)
        abort ();
      regs_ever_live[REGNO (in_rtx)] = 0;
      regs_ever_live[newreg] = 1;
      REGNO (in_rtx) = newreg;
      in_rtx->used = 1;
    }

  if (GET_RTX_CLASS (GET_CODE (in_rtx)) == 'i')
    {
      /* Inside a SEQUENCE, we find insns.
         Renumber just the patterns of these insns,
         just as we do for the top-level insns.  */
      leaf_renumber_regs_insn (PATTERN (in_rtx));
      return;
    }

  format_ptr = GET_RTX_FORMAT (GET_CODE (in_rtx));

  for (i = 0; i < GET_RTX_LENGTH (GET_CODE (in_rtx)); i++)
    switch (*format_ptr++)
      {
      case 'e':
        leaf_renumber_regs_insn (XEXP (in_rtx, i));
        break;

      case 'E':
        if (NULL != XVEC (in_rtx, i))
          {
            for (j = 0; j < XVECLEN (in_rtx, i); j++)
              leaf_renumber_regs_insn (XVECEXP (in_rtx, i, j));
          }
        break;

      case 'S':
      case 's':
      case '0':
      case 'i':
      case 'w':
      case 'n':
      case 'u':
        break;

      default:
        abort ();
      }
}
#endif